diff --git a/bin/espruino-cli.js b/bin/espruino-cli.js
index 63e2ccc..b52e51f 100755
--- a/bin/espruino-cli.js
+++ b/bin/espruino-cli.js
@@ -47,6 +47,12 @@ function getHelp() {
    "                               (bluetooth is not currently supported).",
    "                               Optionally skip N first bytes of the bin file.",
    "",
+   "  --loglevel 0             : Set loglevel (0-3). Default is 3",
+   "                               0 = Log errors",
+   "                               1 = Log errors and non-debug messages",
+   "                               2 = Log errors, non-debug messages and warnings",
+   "                               3 = Log errors, non-debug messages, warnings and debug messages",
+   "",
    "If no file, command, or firmware update is specified, this will act",
    "as a terminal for communicating directly with Espruino. Press Ctrl-C",
    "twice to exit.",
@@ -167,6 +173,9 @@ for (var i=2;i<process.argv.length;i++) {
    } else if (arg=="--sleep") {
      i++; args.sleepAfterUpload = parseFloat(next);
      if (!isNextValidNumber(next)) throw new Error("Expecting a number argument to --sleep");
+   } else if (arg=="--loglevel") {
+     i++; args.logLevel = Number(next);
+     if (!isNextValidNumber(next)) throw new Error("Expecting a number argument (0-3) to --loglevel");
    } else throw new Error("Unknown Argument '"+arg+"', try --help");
  } else {
    if ("file" in args)
@@ -848,4 +857,6 @@ function main() {
 }
 
 // Start up
-require('../index.js').init(main);
+require('../index.js').init(args.logLevel !== undefined ? {
+  logLevel: args.logLevel
+} : undefined, main);
diff --git a/core/codeWriter.js b/core/codeWriter.js
index 159eebf..c8fda57 100644
--- a/core/codeWriter.js
+++ b/core/codeWriter.js
@@ -92,7 +92,7 @@
     for (var i=0;i<code.length;i++) {
       var ch = code.charCodeAt(i);
       if ((ch<32 || ch>255) && ch!=9/*Tab*/ && ch!=10/*LF*/ && ch!=13/*CR*/) {
-        console.warn("Funky character code "+ch+" at position "+i+". Replacing with ?");
+        logger.warn("Funky character code "+ch+" at position "+i+". Replacing with ?");
         code = code.substr(0,i)+"?"+code.substr(i+1);
       }
     }
diff --git a/core/config.js b/core/config.js
index 5fb71f7..b967533 100644
--- a/core/config.js
+++ b/core/config.js
@@ -38,17 +38,17 @@
     if (typeof chrome !== 'undefined' && chrome.storage) {
       chrome.storage.sync.get( "CONFIGS", function (data) {
         var value = data["CONFIGS"];
-        console.log("GET chrome.storage.sync = "+JSON.stringify(value));
+        logger.debug("GET chrome.storage.sync = "+JSON.stringify(value));
         callback(value);
       });
     } else if (typeof window !== 'undefined' && window.localStorage) {
       var data = {};
       var value = window.localStorage.getItem("CONFIG");
-      console.log("GET window.localStorage = "+JSON.stringify(value));
+      logger.debug("GET window.localStorage = "+JSON.stringify(value));
       try {
         data = JSON.parse(value);
       } catch (e) {
-        console.log("Invalid config data");
+        logger.error("Invalid config data");
       }
       callback(data);
     } else if (typeof document != "undefined") {
@@ -61,7 +61,7 @@
           var json = atob(cookie);
           data = JSON.parse(json);
         } catch (e) {
-          console.log("Got ", e, " while reading info");
+          logger.error("Got ", e, " while reading info");
         }
       }
       callback(data);
@@ -72,10 +72,10 @@
 
   function _set(data) {
     if (typeof chrome !== 'undefined' && chrome.storage) {
-      console.log("SET chrome.storage.sync = "+JSON.stringify(data,null,2));
+      logger.debug("SET chrome.storage.sync = "+JSON.stringify(data,null,2));
       chrome.storage.sync.set({ CONFIGS : data });
     } else if (typeof window !== 'undefined' && window.localStorage) {
-      console.log("SET window.localStorage = "+JSON.stringify(data,null,2));
+      logger.debug("SET window.localStorage = "+JSON.stringify(data,null,2));
       window.localStorage.setItem("CONFIG",JSON.stringify(data));
     } else if (typeof document != "undefined") {
       document.cookie = "CONFIG="+btoa(JSON.stringify(data));
@@ -88,7 +88,7 @@
         if (key=="set") continue;
         Espruino.Config[key] = value[key];
         if (Espruino.Core.Config.data[key] !== undefined &&
-            Espruino.Core.Config.data[key].onChange !== undefined)
+          Espruino.Core.Config.data[key].onChange !== undefined)
           Espruino.Core.Config.data[key].onChange(value[key]);
       }
       if (callback!==undefined)
@@ -146,7 +146,7 @@
           found = true;
 
       if (!found) {
-        console.warn("Section named "+c.section+" was not added with Config.addSection");
+        logger.warn("Section named "+c.section+" was not added with Config.addSection");
         sections[c.section] = {
             name : c.section,
             sortOrder : 0
diff --git a/core/env.js b/core/env.js
index 19dafce..1ff74af 100644
--- a/core/env.js
+++ b/core/env.js
@@ -57,7 +57,7 @@
         try {
           json = JSON.parse(result);
         } catch (e) {
-          console.log("JSON parse failed - " + e + " in " + JSON.stringify(result));
+          logger.error("JSON parse failed - " + e + " in " + JSON.stringify(result));
         }
       }
       if (Object.keys(json).length==0) {
diff --git a/core/flasher.js b/core/flasher.js
index abaa9a6..56881db 100644
--- a/core/flasher.js
+++ b/core/flasher.js
@@ -33,18 +33,18 @@
       callback("Can't find STM32 bootloader. Make sure the chip is reset into bootloader mode by holding down BTN1 while pressing RST");
     }, (timeout==undefined)?10000:timeout);
     var iPoll = setInterval(function() {
-      console.log("Sending... 0x7F");
+      logger.debug("Sending... 0x7F");
       Espruino.Core.Serial.write("\x7f", false);
     }, 70);
     dataReceived = function (c) {
-      console.log("got "+c);
+      logger.debug("got "+c);
       if (c==ACK || c==NACK) {
         clearTimeout(iTimeout);
         clearInterval(iPoll);
         setStatus("Initialised.");
         // wait for random extra data...
         dataReceived = function(c){
-          console.log("Already ACKed but got "+c);
+          logger.debug("Already ACKed but got "+c);
         };
         setTimeout(function() {
           dataReceived = undefined;
@@ -114,7 +114,7 @@
     // Extended erase
     sendCommand(0x44, function(err) {
       if (err) { callback(err); return; }
-      console.log("We may be some time...");
+      logger.debug("We may be some time...");
       sendData([0xFF,0xFF], function(err) {
         if (err) { callback(err); return; }
         callback(undefined);
@@ -123,25 +123,25 @@
   };
 
   var readData = function(callback, addr, readBytes) {
-    console.log("Reading "+readBytes+" bytes from 0x"+addr.toString(16)+"...");
+    logger.debug("Reading "+readBytes+" bytes from 0x"+addr.toString(16)+"...");
     // send read command
     sendCommand(0x11, function(err) {
       if (err) {
-        console.log("Error sending command ("+err+").");
+        logger.error("Error sending command ("+err+").");
         callback(err);
         return;
       }
       // send address
       sendData([(addr>>24)&0xFF,(addr>>16)&0xFF,(addr>>8)&0xFF,addr&0xFF], function(err) {
         if (err) {
-          console.log("Error sending address. ("+err+")");
+          logger.error("Error sending address. ("+err+")");
           callback(err);
           return;
         }
         // send amount of bytes we want
         sendData([readBytes-1], function(err) {
           if (err) {
-            console.log("Error while reading. ("+err+")");
+            logger.error("Error while reading. ("+err+")");
             callback(err);
             return;
           }
@@ -170,13 +170,13 @@
     readData(function(err, data) {
       if (err) return callback(err);
       var word = (data[3]<<24) | (data[2]<<16) | (data[1]<<8) | data[0];
-      console.log("RCC->CFGR = "+word);
+      logger.debug("RCC->CFGR = "+word);
       var newword = (word&0xFFFFF8FF) | 0x00000400;
       if (newword==word) {
-        console.log("RCC->CFGR is correct");
+        logger.debug("RCC->CFGR is correct");
         callback(undefined);
       } else {
-        console.log("Setting RCC->CFGR to "+newword);
+        logger.debug("Setting RCC->CFGR to "+newword);
         writeData(callback, RCC_CFGR, [newword&0xFF, (newword>>8)&0xFF, (newword>>16)&0xFF, (newword>>24)&0xFF]);
       }
     }, RCC_CFGR, 4);
@@ -184,11 +184,11 @@
 
   var writeData = function(callback, addr, data) {
     if (data.length>256) callback("Writing too much data");
-    console.log("Writing "+data.length+" bytes at 0x"+addr.toString(16)+"...");
+    logger.debug("Writing "+data.length+" bytes at 0x"+addr.toString(16)+"...");
     // send write command
     sendCommand(0x31, function(err) {
       if (err) {
-        console.log("Error sending command ("+err+"). retrying...");
+        logger.error("Error sending command ("+err+"). retrying...");
         initialiseChip(function (err) {
           if (err) callback(err);
           else writeData(callback, addr, data);
@@ -198,7 +198,7 @@
       // send address
       sendData([(addr>>24)&0xFF,(addr>>16)&0xFF,(addr>>8)&0xFF,addr&0xFF], function(err) {
         if (err) {
-          console.log("Error sending address ("+err+"). retrying...");
+          logger.error("Error sending address ("+err+"). retrying...");
           initialiseChip(function (err) {
             if (err) callback(err);
             else writeData(callback, addr, data);
@@ -212,7 +212,7 @@
         // send data
         sendData(sData, function(err) {
           if (err) {
-            console.log("Error while writing ("+err+"). retrying...");
+            logger.error("Error while writing ("+err+"). retrying...");
             initialiseChip(function (err) {
               if (err) callback(err);
               else writeData(callback, addr, data);
@@ -227,7 +227,7 @@
 
   var writeAllData = function(binary, flashOffset, callback) {
     var chunkSize = 256;
-    console.log("Writing "+binary.byteLength+" bytes");
+    logger.debug("Writing "+binary.byteLength+" bytes");
     Espruino.Core.Status.setStatus("Writing flash...",  binary.byteLength);
     var writer = function(offset) {
       if (offset>=binary.byteLength) {
@@ -250,7 +250,7 @@
   var readAllData = function(binaryLength, flashOffset, callback) {
     var data = new Uint8Array(flashOffset);
     var chunkSize = 256;
-    console.log("Reading "+binaryLength+" bytes");
+    logger.debug("Reading "+binaryLength+" bytes");
     Espruino.Core.Status.setStatus("Reading flash...",  binaryLength);
     var reader = function(offset) {
       if (offset>=binaryLength) {
@@ -302,7 +302,7 @@
       for (var i=0;i<bufView.length;i++) bytesReceived.push(bufView[i]);
       if (dataReceived!==undefined) {
         for (var i=0;i<bytesReceived.length;i++) {
-          if (dataReceived===undefined) console.log("OH NO!");
+          if (dataReceived===undefined) logger.error("OH NO!");
           dataReceived(bytesReceived[i]);
         }
         bytesReceived = [];
@@ -359,7 +359,7 @@
   function flashDevice(url, flashOffset, callback, statusCallback) {
     Espruino.Core.Utils.getBinaryURL(url, function (err, binary) {
       if (err) { callback(err); return; }
-      console.log("Downloaded "+binary.byteLength+" bytes");
+      logger.debug("Downloaded "+binary.byteLength+" bytes");
       flashBinaryToDevice(binary, flashOffset, callback, statusCallback);
     });
   };
@@ -374,7 +374,7 @@
       for (var i=0;i<bufView.length;i++) bytesReceived.push(bufView[i]);
       if (dataReceived!==undefined) {
         for (var i=0;i<bytesReceived.length;i++) {
-          if (dataReceived===undefined) console.log("OH NO!");
+          if (dataReceived===undefined) logger.error("OH NO!");
           dataReceived(bytesReceived[i]);
         }
         bytesReceived = [];
@@ -397,7 +397,7 @@
       if (err) return finish(err);
       var data = new Uint8Array([0x04,0x00,0xFA,0x05]);
       var addr = 0xE000ED0C;
-      console.log("Writing "+data.length+" bytes at 0x"+addr.toString(16)+"...");
+      logger.debug("Writing "+data.length+" bytes at 0x"+addr.toString(16)+"...");
       // send write command
       sendCommand(0x31, function(err) {
         if (err) return finish(err);
diff --git a/core/flasherESP8266.js b/core/flasherESP8266.js
index 90e2c8a..0a61074 100644
--- a/core/flasherESP8266.js
+++ b/core/flasherESP8266.js
@@ -48,10 +48,10 @@
       var l = uartLine.split("\n");
         while(l.length>1) {
           var a = l.shift();
-          console.log(">>>",a);
+          logger.debug(">>>",a);
           try {
           if (packetHandler) packetHandler(Espruino.Core.Utils.parseJSONish(a));
-          } catch(e) { console.log("Unable to decode"); }
+          } catch(e) { logger.error("Unable to decode"); }
         }
         uartLine = l[0];
     });
@@ -74,11 +74,11 @@
     then(() => cmdFlash(options)).
     then(() => unsetupEspruino(options)).
     then(function() {
-      console.log("Complete!");
+      logger.debug("Complete!");
       finish();
       if (options.cbDone) options.cbDone();
     }).catch(function(error) {
-      console.log("Error!", error);
+      logger.log("Error!", error);
       finish();
       if (options.cbDone) options.cbDone(error);
     });
@@ -117,7 +117,7 @@ function setupEspruino(options) {
   return new Promise((resolve,reject)=>{
     Espruino.Core.Serial.write('\x03\x10reset()\n', false, function() {
       setTimeout(function() {
-          console.log("Start Wifi, add handler");
+          logger.debug("Start Wifi, add handler");
           Espruino.Core.Serial.write(`\x10${options.serialDevice}.setup(115200, { rx: ${options.serialRx}, tx : ${options.serialTx} });
 \x10var packetHandler, packetData="", OUT=eval(process.env.CONSOLE);
 \x10${options.serialDevice}.on('data', function(d) {
@@ -144,7 +144,7 @@ function setupEspruino(options) {
 \x10${options.chBoot?`digitalWrite(${options.chBoot}, 0);`:`` /* into of boot mode */}
 \x10${options.chPD?`digitalWrite(${options.chPD}, 1);`:`` /* turn on wifi */}
 `, false, function() {
-            console.log("Handler added");
+            logger.debug("Handler added");
             resolve();
           });
         }, 1000);
@@ -164,7 +164,7 @@ function unsetupEspruino(options) {
 }
 
 function cmdSync(options) {
-  console.log("Syncing...");
+  logger.debug("Syncing...");
   return new Promise((resolve,reject)=>{
     var success = false;
     var interval;
@@ -175,7 +175,7 @@ function cmdSync(options) {
           interval = undefined;
         }
         packetHandler = undefined;
-        console.log("Sync complete!");
+        logger.debug("Sync complete!");
         setTimeout(function() {
           // allow time for other responses
           resolve();
@@ -202,7 +202,7 @@ function cmdSync(options) {
 function cmdFlash(options) {
   var binary = new Uint8Array(options.binary);
   var blockCount = Math.floor((binary.length + (BLOCK_SIZE-1)) / BLOCK_SIZE);
-  console.log(`Start Flashing, ${blockCount} blocks of ${BLOCK_SIZE} bytes`);
+  logger.debug(`Start Flashing, ${blockCount} blocks of ${BLOCK_SIZE} bytes`);
   var d = new Uint32Array([
     blockCount*BLOCK_SIZE, // erase size
     blockCount, // # packets
@@ -211,7 +211,7 @@ function cmdFlash(options) {
   ]);
   var idx = 0;
   return sendCmd(options, 2 /* FLASH_BEGIN */, new Uint8Array(d.buffer)).then(function flash() {
-    console.log("Block "+idx);
+    logger.debug("Block "+idx);
     if (options.cbStatus) options.cbStatus(`Writing Block ${idx} / ${blockCount}`, idx / blockCount);
     if (idx>=blockCount) return true;
     d = new Uint8Array(16 + BLOCK_SIZE);
diff --git a/core/modules.js b/core/modules.js
index c7c38fb..9c5ab5b 100644
--- a/core/modules.js
+++ b/core/modules.js
@@ -123,7 +123,7 @@
     var fullModuleName = data.moduleName;
 
     // try and load the module the old way...
-    console.log("loadModule("+fullModuleName+")");
+    logger.debug("loadModule("+fullModuleName+")");
 
     var urls = []; // Array of where to look for this module
     var modName; // Simple name of the module
@@ -167,16 +167,16 @@
   function moduleLoaded(resolve, requires, modName, data, loadedModuleData, alreadyMinified){
     // Check for any modules used from this module that we don't already have
     var newRequires = getModulesRequired(data);
-    console.log(" - "+modName+" requires "+JSON.stringify(newRequires));
+    logger.debug(" - "+modName+" requires "+JSON.stringify(newRequires));
     // if we need new modules, set them to load and get their promises
     var newPromises = [];
     for (var i in newRequires) {
       if (requires.indexOf(newRequires[i])<0) {
-        console.log("   Queueing "+newRequires[i]);
+        logger.debug("   Queueing "+newRequires[i]);
         requires.push(newRequires[i]);
         newPromises.push(loadModule(requires, newRequires[i], loadedModuleData));
       } else {
-        console.log("   Already loading "+newRequires[i]);
+        logger.debug("   Already loading "+newRequires[i]);
       }
     }
 
diff --git a/core/serial.js b/core/serial.js
index 310a4a4..eff572b 100644
--- a/core/serial.js
+++ b/core/serial.js
@@ -78,7 +78,7 @@ To add a new serial device, you must add an object to
 
     var devices = Espruino.Core.Serial.devices;
     for (var i=0;i<devices.length;i++) {
-      console.log("  - Initialising Serial "+devices[i].name);
+      logger.debug("  - Initialising Serial "+devices[i].name);
       if (devices[i].init)
         devices[i].init();
     }
@@ -161,7 +161,7 @@ To add a new serial device, you must add an object to
         serialPort = serialPort.toLowerCase();
       } else {
         if (attempts>0) {
-          console.log("Port "+JSON.stringify(serialPort)+" not found - checking ports again ("+attempts+" attempts left)");
+          logger.warn("Port "+JSON.stringify(serialPort)+" not found - checking ports again ("+attempts+" attempts left)");
           setTimeout(function() {
             getPorts(function() {
               openSerialInternal(serialPort, connectCallback, disconnectCallback, attempts-1);
@@ -169,7 +169,7 @@ To add a new serial device, you must add an object to
           }, 500);
           return;
         } else {
-          console.error("Port "+JSON.stringify(serialPort)+" not found");
+          logger.error("Port "+JSON.stringify(serialPort)+" not found");
           return connectCallback(undefined);
         }
       }
@@ -186,13 +186,13 @@ To add a new serial device, you must add an object to
     currentDevice.open(serialPort, function(cInfo) {  // CONNECT
       if (!cInfo) {
 //        Espruino.Core.Notifications.error("Unable to connect");
-        console.error("Unable to open device (connectionInfo="+cInfo+")");
+        logger.error("Unable to open device (connectionInfo="+cInfo+")");
         connectCallback(undefined);
         connectCallback = undefined;
       } else {
         connectionInfo = cInfo;
         connectedPort = serialPort;
-        console.log("Connected", cInfo);
+        logger.debug("Connected", cInfo);
         if (connectionInfo.portName)
           portInfo.portName = connectionInfo.portName;
         Espruino.callProcessor("connected", portInfo, function() {
@@ -201,12 +201,12 @@ To add a new serial device, you must add an object to
         });
       }
     }, function(data) { // RECEIEVE DATA
-      if (!(data instanceof ArrayBuffer)) console.warn("Serial port implementation is not returning ArrayBuffers");
+      if (!(data instanceof ArrayBuffer)) logger.warn("Serial port implementation is not returning ArrayBuffers");
       if (Espruino.Config.SERIAL_FLOW_CONTROL) {
         var u = new Uint8Array(data);
         for (var i=0;i<u.length;i++) {
           if (u[i]==17) { // XON
-            console.log("XON received => resume upload");
+            logger.debug("XON received => resume upload");
             flowControlXOFF = false;
             if (flowControlTimeout) {
               clearTimeout(flowControlTimeout);
@@ -214,12 +214,12 @@ To add a new serial device, you must add an object to
             }
           }
           if (u[i]==19) { // XOFF
-            console.log("XOFF received => pause upload");
+            logger.debug("XOFF received => pause upload");
             flowControlXOFF = true;
             if (flowControlTimeout)
               clearTimeout(flowControlTimeout);
             flowControlTimeout = setTimeout(function() {
-              console.log("XOFF timeout => resume upload anyway");
+              logger.debug("XOFF timeout => resume upload anyway");
               flowControlXOFF = false;
               flowControlTimeout = undefined;
             }, FLOW_CONTROL_RESUME_TIMEOUT);
@@ -260,7 +260,7 @@ To add a new serial device, you must add an object to
     for (var i=0; i<str.length; i++) {
       var ch = str.charCodeAt(i);
       if (ch>=256) {
-        console.warn("Attempted to send non-8 bit character - code "+ch);
+        logger.warn("Attempted to send non-8 bit character - code "+ch);
         ch = "?".charCodeAt(0);
       }
       bufView[i] = ch;
@@ -273,7 +273,7 @@ To add a new serial device, you must add an object to
       currentDevice.close();
       currentDevice = undefined;
     } else
-      console.error("Close called, but serial port not open");
+      logger.error("Close called, but serial port not open");
   };
 
   var isConnected = function() {
@@ -327,7 +327,7 @@ To add a new serial device, you must add an object to
       writeData[0].showStatus &= writeData[0].data.length>writeData[0].blockSize;
       if (writeData[0].showStatus) {
         Espruino.Core.Status.setStatus("Sending...", writeData[0].data.length);
-        console.log("---> "+JSON.stringify(writeData[0].data));
+        logger.debug("---> "+JSON.stringify(writeData[0].data));
       }
     }
 
@@ -362,7 +362,7 @@ To add a new serial device, you must add an object to
       if (split.match) writeData[0].nextSplit = split;
       split = { start:0, end:writeData[0].blockSize, delay:0 };
     }
-    if (split.match) console.log("Splitting for "+split.reason+", delay "+split.delay);
+    if (split.match) logger.debug("Splitting for "+split.reason+", delay "+split.delay);
     // Only send some of the data
     if (writeData[0].data.length>split.end) {
       if (slowWrite && split.delay==0) split.delay=50;
@@ -424,10 +424,10 @@ To add a new serial device, you must add an object to
     "isSlowWrite": function() { return slowWrite; },
     "setSlowWrite": function(isOn, force) {
       if ((!force) && Espruino.Config.SERIAL_THROTTLE_SEND) {
-        console.log("ForceThrottle option is set - set Slow Write = true");
+        logger.debug("ForceThrottle option is set - set Slow Write = true");
         isOn = true;
       } else
-        console.log("Set Slow Write = "+isOn);
+        logger.debug("Set Slow Write = "+isOn);
       slowWrite = isOn;
     },
     "setBinary": function(isOn) {
diff --git a/core/serial_chrome_serial.js b/core/serial_chrome_serial.js
index 8950626..dfce371 100644
--- a/core/serial_chrome_serial.js
+++ b/core/serial_chrome_serial.js
@@ -20,12 +20,12 @@ Author: Gordon Williams (gw@pur3.co.uk)
 
 (function() {
   if (typeof chrome === 'undefined' || chrome.serial===undefined) {
-    console.log("No chrome.serial - Chrome Serial disabled");
+    logger.debug("No chrome.serial - Chrome Serial disabled");
     return;
   }
   if (chrome.serial.getDevices===undefined) {
     // wrong chrome version
-    console.log("Chrome does NOT have post-M33 serial API");
+    logger.debug("Chrome does NOT have post-M33 serial API");
     return;
   }
 
@@ -61,12 +61,12 @@ Author: Gordon Williams (gw@pur3.co.uk)
     chrome.serial.connect(serialPort, {bitrate: parseInt(Espruino.Config.BAUD_RATE)},
       function(cInfo) {
         if (!cInfo) {
-          console.log("Unable to open device (connectionInfo="+cInfo+")");
+          logger.error("Unable to open device (connectionInfo="+cInfo+")");
           openCallback(undefined);
         } else {
           connectionInfo = cInfo;
           connectedPort = serialPort;
-          console.log(cInfo);
+          logger.debug(cInfo);
           openCallback(cInfo);
         }
     });
@@ -91,7 +91,7 @@ Author: Gordon Williams (gw@pur3.co.uk)
   });
 
   chrome.serial.onReceiveError.addListener(function(errorInfo) {
-    console.error("RECEIVE ERROR:", JSON.stringify(errorInfo));
+    logger.error("RECEIVE ERROR:", JSON.stringify(errorInfo));
     closeSerial();
   });
 
diff --git a/core/serial_chrome_socket.js b/core/serial_chrome_socket.js
index 7c458a6..427629d 100644
--- a/core/serial_chrome_socket.js
+++ b/core/serial_chrome_socket.js
@@ -18,7 +18,7 @@ Author: Patrick Van Oosterwijck (patrick@silicognition.com)
 
 (function() {
   if (typeof chrome === 'undefined' || chrome.sockets===undefined) {
-    console.log("No chrome.sockets - Chrome Socket disabled");
+    logger.debug("No chrome.sockets - Chrome Socket disabled");
     return;
   }
 
@@ -52,7 +52,7 @@ Author: Patrick Van Oosterwijck (patrick@silicognition.com)
 
   var openSerial=function(serialPort, openCallback, receiveCallback, disconnectCallback) {
     if (serialPort.substr(0,8)!='TCP/IP: ') {
-      console.error("Invalid connection "+JSON.stringify(serialPort));
+      logger.error("Invalid connection "+JSON.stringify(serialPort));
       return;
     }
     var host = serialPort.substr(8);
@@ -70,7 +70,7 @@ Author: Patrick Van Oosterwijck (patrick@silicognition.com)
       chrome.sockets.tcp.connect(createInfo.socketId,
           host, port, function (result) {
         if (result < 0) {
-          console.log("Failed to open socket " + host+":"+port);
+          logger.error("Failed to open socket " + host+":"+port);
           openCallback(undefined);
         } else {
           connectionInfo = { socketId: createInfo.socketId };
@@ -106,7 +106,7 @@ Author: Patrick Van Oosterwijck (patrick@silicognition.com)
   chrome.sockets.tcp.onReceiveError.addListener(function(info) {
     if (info.socketId != connectionInfo.socketId)
       return;
-    console.error("RECEIVE ERROR:", JSON.stringify(info));
+    logger.error("RECEIVE ERROR:", JSON.stringify(info));
     connectionDisconnectCallback();
   });
 
diff --git a/core/serial_frame.js b/core/serial_frame.js
index 92fb605..9c4d007 100644
--- a/core/serial_frame.js
+++ b/core/serial_frame.js
@@ -9,12 +9,12 @@ Use embed.js on the client side to link this in.
 
 (function() {
   if (typeof navigator == "undefined" || typeof window == "undefined") {
-    console.log("serial_frame: Not running in a browser");
+    logger.debug("serial_frame: Not running in a browser");
     return;
   }
   if (typeof window.parent == undefined ||
       window.parent === window) {
-    console.log("serial_frame: Not running inside an iframe");
+    logger.debug("serial_frame: Not running inside an iframe");
     return;
   }
 
@@ -50,10 +50,10 @@ Use embed.js on the client side to link this in.
       } break;
       case "connect":
         if (Espruino.Core.Serial.isConnected())
-          console.error("serial_frame: already connected");
+          logger.debug("serial_frame: already connected");
 
         Espruino.Core.MenuPortSelector.connectToPort(event.data, function() {
-          console.log("serial_frame: connected");
+          logger.debug("serial_frame: connected");
         });
         break;
       case "connected": if (callbacks.connected) {
@@ -70,7 +70,7 @@ Use embed.js on the client side to link this in.
       } break;
       case "receive": if (callbacks.receive) {
         if (typeof event.data!="string")
-          console.error("serial_frame: receive event expecting data string");
+          logger.warn("serial_frame: receive event expecting data string");
         callbacks.receive(Espruino.Core.Utils.stringToArrayBuffer(event.data));
       } break;
       case "setMaxWriteLength": {
@@ -78,7 +78,7 @@ Use embed.js on the client side to link this in.
         device.maxWriteLength = parseInt(event.data);
       } break;
       default:
-        console.error("Unknown event type ",event.type);
+        logger.error("Unknown event type ",event.type);
         break;
     }
   });
@@ -105,11 +105,11 @@ Use embed.js on the client side to link this in.
         callbacks.ports = undefined;
         callback([], false/*instantPorts*/);
         ERROR = "getPorts timeout, disabling";
-        console.error("serial_frame: "+ERROR);
+        logger.error("serial_frame: "+ERROR);
       },100);
       callbacks.ports = function(d) {
         if (!timeout) {
-          console.error("serial_frame: ports received after timeout");
+          logger.error("serial_frame: ports received after timeout");
           return;
         }
         clearTimeout(timeout);
diff --git a/core/serial_noble.js b/core/serial_noble.js
index 7618a6b..48662c7 100644
--- a/core/serial_noble.js
+++ b/core/serial_noble.js
@@ -50,7 +50,7 @@
   function nobleExceptionHandler(err) {
     if (err.toString().includes("ENODEV")) {
       process.removeListener('uncaughtException', nobleExceptionHandler);
-      console.log("Noble: "+err.toString()+" - disabling.");
+      logger.error("Noble: "+err.toString()+" - disabling.");
       errored = true;
     } else throw err;
   }
@@ -64,7 +64,7 @@
         noble = require('@abandonware/noble');
       }
     } catch (e) {
-      console.log("Noble: module couldn't be loaded, no node.js Bluetooth Low Energy\n", e);
+      logger.error("Noble: module couldn't be loaded, no node.js Bluetooth Low Energy\n", e);
       // super nasty workaround for https://github.com/sandeepmistry/noble/issues/502
       process.removeAllListeners('exit');
       errored = true;
@@ -73,12 +73,12 @@
 
     noble.on('stateChange', function(state) {
       process.removeListener('uncaughtException', nobleExceptionHandler);
-      console.log("Noble: stateChange -> "+state);
+      logger.debug("Noble: stateChange -> "+state);
       if (state=="poweredOn") {
         if (Espruino.Config.WEB_BLUETOOTH) {
           // Everything has already initialised, so we must disable
           // web bluetooth this way instead
-          console.log("Noble: Disable Web Bluetooth as we have Noble instead");
+          logger.debug("Noble: Disable Web Bluetooth as we have Noble instead");
           Espruino.Config.WEB_BLUETOOTH = false;
         }
         initialised = true;
@@ -103,16 +103,16 @@
                            dev.advertisement.serviceUuids.indexOf(NORDIC_SERVICE)>=0;
       if (hasUartService ||
           Espruino.Core.Utils.isRecognisedBluetoothDevice(name)) {
-        console.log("Noble: Found UART device:", name, dev.address);
+        logger.debug("Noble: Found UART device:", name, dev.address);
         newDevices.push({ path: dev.address, description: name, type: "bluetooth", rssi: dev.rssi });
         btDevices[dev.address] = dev;
-      } else console.log("Noble: Found device:", name, dev.address);
+      } else logger.debug("Noble: Found device:", name, dev.address);
     });
 
     // if we didn't initialise for whatever reason, keep going anyway
     setTimeout(function() {
       if (initialised) return;
-      console.log("Noble: Didn't initialise in 10 seconds, disabling.");
+      logger.error("Noble: Didn't initialise in 10 seconds, disabling.");
       errored = true;
     }, 10000);
     return true;
@@ -123,24 +123,24 @@
       clearTimeout(scanStopTimeout);
       scanStopTimeout = undefined;
     } else {
-      console.log("Noble: Starting scan");
+      logger.debug("Noble: Starting scan");
       lastDevices = [];
       newDevices = [];
       noble.startScanning([], true);
     }
     scanStopTimeout = setTimeout(function () {
       scanStopTimeout = undefined;
-      console.log("Noble: Stopping scan");
+      logger.debug("Noble: Stopping scan");
       noble.stopScanning();
     }, 3000);
   }
 
   var getPorts = function (callback) {
     if (errored || !Espruino.Config.BLUETOOTH_LOW_ENERGY) {
-      console.log("Noble: getPorts - disabled");
+      logger.error("Noble: getPorts - disabled");
       callback([], true/*instantPorts*/);
     } else if (!initialised) {
-      console.log("Noble: getPorts - initialising...");
+      logger.debug("Noble: getPorts - initialising...");
       if (!noble)
         if (!startNoble())
           return callback([], true/*instantPorts*/);
@@ -175,13 +175,13 @@
     if (scanStopTimeout) {
       clearTimeout(scanStopTimeout);
       scanStopTimeout = undefined;
-      console.log("Noble: Stopping scan (openSerial)");
+      logger.debug("Noble: Stopping scan (openSerial)");
       noble.stopScanning();
     }
 
     txInProgress = false;
 
-    console.log("BT> Connecting");
+    logger.debug("BT> Connecting");
     btDevice.on('disconnect', function() {
       txCharacteristic = undefined;
       rxCharacteristic = undefined;
@@ -192,21 +192,21 @@
 
     btDevice.connect(function (error) {
       if (error) {
-        console.log("BT> ERROR Connecting");
+        logger.error("BT> ERROR Connecting");
         btDevice = undefined;
         return openCallback();
       }
-      console.log("BT> Connected");
+      logger.debug("BT> Connected");
 
       btDevice.discoverAllServicesAndCharacteristics(function(error, services, characteristics) {
         var btUARTService = findByUUID(services, NORDIC_SERVICE);
         txCharacteristic = findByUUID(characteristics, NORDIC_TX);
         rxCharacteristic = findByUUID(characteristics, NORDIC_RX);
         if (error || !btUARTService || !txCharacteristic || !rxCharacteristic) {
-          console.log("BT> ERROR getting services/characteristics");
-          console.log("Service "+btUARTService);
-          console.log("TX "+txCharacteristic);
-          console.log("RX "+rxCharacteristic);
+          logger.error("BT> ERROR getting services/characteristics");
+          logger.error("Service "+btUARTService);
+          logger.error("TX "+txCharacteristic);
+          logger.error("RX "+rxCharacteristic);
           btDevice.disconnect();
           txCharacteristic = undefined;
           rxCharacteristic = undefined;
@@ -235,15 +235,15 @@
     if (txCharacteristic === undefined) return;
 
     if (data.length>NORDIC_TX_MAX_LENGTH) {
-      console.error("BT> TX length >"+NORDIC_TX_MAX_LENGTH);
+      logger.error("BT> TX length >"+NORDIC_TX_MAX_LENGTH);
       return callback();
     }
     if (txInProgress) {
-      console.error("BT> already sending!");
+      logger.error("BT> already sending!");
       return callback();
     }
 
-    console.log("BT> send "+JSON.stringify(data));
+    logger.debug("BT> send "+JSON.stringify(data));
     txInProgress = true;
     try {
       txCharacteristic.write(Espruino.Core.Utils.stringToBuffer(data), false, function() {
@@ -251,7 +251,7 @@
         return callback();
       });
     } catch (e) {
-      console.log("BT> SEND ERROR " + e);
+      logger.error("BT> SEND ERROR " + e);
       closeSerial();
     }
   };
diff --git a/core/serial_node_serial.js b/core/serial_node_serial.js
index 1b994f5..da7cca1 100644
--- a/core/serial_node_serial.js
+++ b/core/serial_node_serial.js
@@ -4,7 +4,7 @@ Gordon Williams (gw@pur3.co.uk)
 (function() {
   // Are we on nw.js with chrome.serial? No need for serialport then!
   if (typeof chrome !== 'undefined' && chrome.serial) {
-    console.log("We have chrome.serial - not using 'serialport' module");
+    logger.debug("We have chrome.serial - not using 'serialport' module");
     return;
   }
   if (typeof require === 'undefined') return;
@@ -12,13 +12,13 @@ Gordon Williams (gw@pur3.co.uk)
   try {
     require.resolve('serialport');    
   } catch (e) {
-    console.log("No 'serialport' module found");
+    logger.error("No 'serialport' module found");
     return;
   }
   try {
     serialport = require('serialport').SerialPort;
   } catch (e) {
-    console.log("Error initialising 'serialport':" + e.toString());
+    logger.error("Error initialising 'serialport':" + e.toString());
     return;
   }
 
@@ -63,7 +63,7 @@ Gordon Williams (gw@pur3.co.uk)
           }), true/*instantPorts*/
       );
     }).catch(function(err) {
-      console.log("serialport error: "+err.toString());
+      logger.error("serialport error: "+err.toString());
       return callback([], true/*instantPorts*/);
     });
   };
diff --git a/core/serial_node_socket.js b/core/serial_node_socket.js
index 11d347b..315290f 100644
--- a/core/serial_node_socket.js
+++ b/core/serial_node_socket.js
@@ -25,7 +25,7 @@ Author: Alfie Kirkpatrick (jugglingcats@akirkpatrick.com)
   try {
     net = require("net");
   } catch (e) {
-    console.log("Require net failed - Node Socket disabled");
+    logger.error("Require net failed - Node Socket disabled");
     return;
   }
 
@@ -43,7 +43,7 @@ Author: Alfie Kirkpatrick (jugglingcats@akirkpatrick.com)
 
   var openSerial = function (serialPort, openCallback, receiveCallback, disconnectCallback) {
     if (serialPort.substr(0, 6) != 'tcp://') {
-      console.error("Invalid connection " + JSON.stringify(serialPort));
+      logger.error("Invalid connection " + JSON.stringify(serialPort));
       return;
     }
     var host = serialPort.substr(6);
@@ -67,7 +67,7 @@ Author: Alfie Kirkpatrick (jugglingcats@akirkpatrick.com)
       }
     });
     socket.on("error", function (info) {
-      console.error("RECEIVE ERROR:", JSON.stringify(info));
+      logger.error("RECEIVE ERROR:", JSON.stringify(info));
       // node will close the connection
     });
     socket.on("end", function () {
diff --git a/core/serial_web_audio.js b/core/serial_web_audio.js
index f2695b6..64f3a3e 100644
--- a/core/serial_web_audio.js
+++ b/core/serial_web_audio.js
@@ -81,10 +81,10 @@
       inputNode = context.createScriptProcessor(4096, 1/*in*/, 1/*out*/);
       window.dontGarbageCollectMePlease = inputNode;
       inputNode.onaudioprocess = audioProcessor;
-      console.log("serial_audio: Audio Sample rate : "+context.sampleRate);
+      logger.debug("serial_audio: Audio Sample rate : "+context.sampleRate);
 
       bitTime = context.sampleRate / BAUD; // intentionally a float
-      console.log("serial_audio: Audio Serial Baud", BAUD, "Bit time", bitTime);
+      logger.debug("serial_audio: Audio Serial Baud", BAUD, "Bit time", bitTime);
     }
 
     navigator.getUserMedia({
@@ -101,7 +101,7 @@
         connected = true;
         openCallback("Hello");
       }, function(e) {
-        console.log('serial_audio: getUserMedia error', e);
+        logger.error('serial_audio: getUserMedia error', e);
         openCallback(undefined);
     });
   };
diff --git a/core/serial_web_bluetooth.js b/core/serial_web_bluetooth.js
index 64aee9f..cb66ce4 100644
--- a/core/serial_web_bluetooth.js
+++ b/core/serial_web_bluetooth.js
@@ -78,7 +78,7 @@
     });
     // If we're ok and have the getDevices extension, use it to remember previously paired devices
     if (getStatus(true)===true && navigator.bluetooth.getDevices) {
-      console.log("BT> bluetooth.getDevices exists - grab known devices");
+      logger.debug("BT> bluetooth.getDevices exists - grab known devices");
       navigator.bluetooth.getDevices().then(devices=>{
         pairedDevices = devices;
       });
@@ -118,7 +118,7 @@
     // Check for pre-paired devices
     btDevice = pairedDevices.find(dev=>dev.name == serialPort);
     if (btDevice) {
-      console.log("BT> Pre-paired Web Bluetooth device already found");
+      logger.debug("BT> Pre-paired Web Bluetooth device already found");
       promise = Promise.resolve(btDevice);
     } else {
       var filters = [];
@@ -126,7 +126,7 @@
         filters.push({ namePrefix: namePrefix });
       });
       filters.push({ services: [ NORDIC_SERVICE ] });
-      console.log("BT> Starting device chooser");
+      logger.debug("BT> Starting device chooser");
       promise = navigator.bluetooth.requestDevice({
           filters: filters,
           optionalServices: [ NORDIC_SERVICE ]});
@@ -134,35 +134,35 @@
     promise.then(function(device) {
       btDevice = device;
       Espruino.Core.Status.setStatus("Connecting to "+btDevice.name);
-      console.log('BT>  Device Name:       ' + btDevice.name);
-      console.log('BT>  Device ID:         ' + btDevice.id);
+      logger.debug('BT>  Device Name:       ' + btDevice.name);
+      logger.debug('BT>  Device ID:         ' + btDevice.id);
       // Was deprecated: Should use getPrimaryServices for this in future
       //console.log('BT>  Device UUIDs:      ' + device.uuids.join('\n' + ' '.repeat(21)));
       btDevice.addEventListener('gattserverdisconnected', function() {
-        console.log("BT> Disconnected (gattserverdisconnected)");
+        logger.debug("BT> Disconnected (gattserverdisconnected)");
         closeSerial();
       }, {once:true});
       return btDevice.gatt.connect();
     }).then(function(server) {
       Espruino.Core.Status.setStatus("Connected to BLE");
-      console.log("BT> Connected");
+      logger.debug("BT> Connected");
       btServer = server;
       return server.getPrimaryService(NORDIC_SERVICE);
     }).then(function(service) {
       Espruino.Core.Status.setStatus("Configuring BLE...");
-      console.log("BT> Got service");
+      logger.debug("BT> Got service");
       btService = service;
       return btService.getCharacteristic(NORDIC_RX);
     }).then(function (characteristic) {
       Espruino.Core.Status.setStatus("Configuring BLE....");
       rxCharacteristic = characteristic;
       setMaxPacketLength(NORDIC_DEFAULT_TX_LENGTH); // set default packet length
-      console.log("BT> RX characteristic:"+JSON.stringify(rxCharacteristic));
+      logger.debug("BT> RX characteristic:"+JSON.stringify(rxCharacteristic));
       rxCharacteristic.addEventListener('characteristicvaluechanged', function(event) {
         // In Chrome 50+, a DataView is returned instead of an ArrayBuffer.
         var value = event.target.value.buffer;
         if (value.byteLength > maxPacketLength) {
-          console.log("BT> Received packet of length "+value.byteLength+" - assuming increased MTU");
+          logger.debug("BT> Received packet of length "+value.byteLength+" - assuming increased MTU");
           setMaxPacketLength(value.byteLength);
         }
         //console.log("BT> RX:"+JSON.stringify(Espruino.Core.Utils.arrayBufferToString(value)));
@@ -175,7 +175,7 @@
     }).then(function (characteristic) {
       Espruino.Core.Status.setStatus("Configuring BLE.....");
       txCharacteristic = characteristic;
-      console.log("BT> TX characteristic:"+JSON.stringify(txCharacteristic));
+      logger.debug("BT> TX characteristic:"+JSON.stringify(txCharacteristic));
     }).then(function() {
       Espruino.Core.Status.setStatus("Configuring BLE.....");
       txInProgress = false;
@@ -187,7 +187,7 @@
         openCallback({ portName : btDevice.name });
       }, 500);
     }).catch(function(error) {
-      console.log('BT> ERROR: ' + error);
+      logger.error('BT> ERROR: ' + error);
       closeSerial({error:error.toString()});
     });
   }
@@ -211,11 +211,11 @@
     if (!txCharacteristic) return;
 
     if (data.length>maxPacketLength) {
-      console.error("BT> TX length >"+maxPacketLength);
+      logger.error("BT> TX length >"+maxPacketLength);
       return callback();
     }
     if (txInProgress) {
-      console.error("BT> already sending!");
+      logger.error("BT> already sending!");
       return callback();
     }
 
@@ -224,7 +224,7 @@
       txInProgress = false;
       callback();
     }).catch(function(error) {
-     console.log('BT> SEND ERROR: ' + error);
+     logger.error('BT> SEND ERROR: ' + error);
      closeSerial();
     });
   }
diff --git a/core/serial_web_serial.js b/core/serial_web_serial.js
index 6cb7100..369ba70 100644
--- a/core/serial_web_serial.js
+++ b/core/serial_web_serial.js
@@ -48,12 +48,12 @@
     });
     // If we're ok and have the getDevices extension, use it to remember previously paired devices
     if (getStatus(true)===true && navigator.serial.getPorts) {
-      console.log("Serial> serial.getPorts exists - grab known devices");
+      logger.debug("Serial> serial.getPorts exists - grab known devices");
       navigator.serial.getPorts().then(devices=>{
         pairedDevices = devices;
       }, err=>{
         getPortsErrorMessage = err.toString();
-        console.log("Serial> "+err.toString());
+        logger.error("Serial> "+err.toString());
       });
     }
   }
@@ -91,10 +91,10 @@
     // Check for pre-paired devices
     serialPort = pairedDevices.find(dev=>getSerialDeviceInfo(dev).path == path);
     if (serialPort) {
-      console.log("Serial> Pre-paired Web Serial device already found");
+      logger.debug("Serial> Pre-paired Web Serial device already found");
       promise = Promise.resolve(serialPort);
     } else {
-      console.log("Serial> Starting device chooser");
+      logger.debug("Serial> Starting device chooser");
       promise = navigator.serial.requestPort({});
     }
     promise.then(function(port) {
@@ -124,7 +124,7 @@
 
       openCallback({ portName : getSerialDeviceInfo(serialPort).path });
     }).catch(function(error) {
-      console.log('Serial> ERROR: ' + error);
+      logger.error('Serial> ERROR: ' + error);
       disconnectCallback();
     });
   }
@@ -148,7 +148,7 @@
     writer.write(Espruino.Core.Utils.stringToArrayBuffer(data)).then(function() {
       callback();
     }).catch(function(error) {
-      console.log('Serial> SEND ERROR: ' + error);
+      logger.error('Serial> SEND ERROR: ' + error);
       closeSerial();
     });
     writer.releaseLock();
diff --git a/core/serial_websocket_local.js b/core/serial_websocket_local.js
index 7c5f188..fadc0ea 100644
--- a/core/serial_websocket_local.js
+++ b/core/serial_websocket_local.js
@@ -4,7 +4,7 @@ Gordon Williams (gw@pur3.co.uk)
 (function() {
 
   if (typeof window == "undefined" || typeof WebSocket == undefined) return;
-  console.log("WebSocket localhost support (EspruinoHost) enabled - running in web browser");
+  logger.debug("WebSocket localhost support (EspruinoHost) enabled - running in web browser");
 
   var WS_ENABLED = true;
   var ws;
@@ -19,7 +19,7 @@ Gordon Williams (gw@pur3.co.uk)
 
   function ensureConnection(callback) {
     if (wsConnecting) {
-      console.log("Waiting for Websocket connection - queueing");
+      logger.debug("Waiting for Websocket connection - queueing");
       wsConnectCallbacks.push(callback);
       return;
     }
@@ -48,7 +48,7 @@ Gordon Williams (gw@pur3.co.uk)
   }
 
   function wsMessage(event) {
-    console.log("Got "+event.data);
+    logger.debug("Got "+event.data);
     try {
       var j = JSON.parse(event.data);
       if (j.type=="list") {
@@ -81,19 +81,19 @@ Gordon Williams (gw@pur3.co.uk)
         }
       } else if (j.type=="write") {
         dataWrittenCallbacks.forEach(function(cb) {
-          console.log("Calling data written cb");
+          logger.debug("Calling data written cb");
           cb();
         });
         dataWrittenCallbacks = [];
       }
     } catch (e) {
-      console.log("Error processing JSON response: "+event.data);
+      logger.error("Error processing JSON response: "+event.data);
     }
   }
 
   function wsClosed(event) {
     ws = undefined;
-    console.log("WebSocket closed");
+    logger.debug("WebSocket closed");
     disconnectCallback();
     disconnectCallback = undefined;
   }
@@ -103,7 +103,7 @@ Gordon Williams (gw@pur3.co.uk)
     ensureConnection(function(err) {
       if (err) {
         WS_ENABLED = false;
-        console.log("Couldn't connect to "+Espruino.Config.WEBSOCKET_URL+" - disabling websockets for this session");
+        logger.error("Couldn't connect to "+Espruino.Config.WEBSOCKET_URL+" - disabling websockets for this session");
         return callback([], false/*instantPorts*/);
       } else {
         listCallbacks.push(callback);
@@ -115,7 +115,7 @@ Gordon Williams (gw@pur3.co.uk)
   var openSerial=function(serialPort, _connectCallback, _receiveCallback, _disconnectCallback) {
     var device = listOfDevices.find(dev=>dev.path==serialPort);
     if (!device) {
-      console.err("Tried to connect to "+serialPort+" but it didn't exist!");
+      logger.err("Tried to connect to "+serialPort+" but it didn't exist!");
       return openCallback(); // open failed
     }
 
@@ -145,7 +145,7 @@ Gordon Williams (gw@pur3.co.uk)
   var writeSerial = function(data, callback) {
     if (!ws) return callback();
     dataWrittenCallbacks.push(callback);
-    console.log(JSON.stringify({"type":"write", data:data}));
+    logger.debug(JSON.stringify({"type":"write", data:data}));
     ws.send(JSON.stringify({"type":"write", data:data}));
   };
 
diff --git a/core/serial_websocket_relay.js b/core/serial_websocket_relay.js
index f984995..28f7554 100644
--- a/core/serial_websocket_relay.js
+++ b/core/serial_websocket_relay.js
@@ -10,10 +10,10 @@ Used for Relay service on espruino.com/ide as well as `npm espruino-web-ide`'s
 
   if (/*window.location.origin=="https://www.espruino.com" || */
       window.location.origin=="https://espruino.github.io") {
-    console.log("Running from github - WebSocket support disabled");
+    logger.debug("Running from github - WebSocket support disabled");
     return;
   }
-  console.log("WebSocket relay support enabled - running in web browser");
+  logger.debug("WebSocket relay support enabled - running in web browser");
 
   var WS_ENABLED = true;
   var ws;
@@ -26,7 +26,7 @@ Used for Relay service on espruino.com/ide as well as `npm espruino-web-ide`'s
       if (!WS_ENABLED) return callback([], true/*instantPorts*/);
       Espruino.Core.Utils.getJSONURL("/serial/ports", function(ports) {
         if (ports===undefined) {
-          console.log("/serial/ports doesn't exist - disabling WebSocket support");
+          logger.error("/serial/ports doesn't exist - disabling WebSocket support");
           WS_ENABLED = false;
           callback([]);
           return;
diff --git a/core/serial_winnus.js b/core/serial_winnus.js
index 8427d38..758aaa5 100644
--- a/core/serial_winnus.js
+++ b/core/serial_winnus.js
@@ -2,17 +2,17 @@
   if (typeof require === 'undefined') return;
   var isWindows = /^win/.test(process.platform);
   if (!isWindows) {
-    console.log("Not on Windows, Winnus not needed");
+    logger.debug("Not on Windows, Winnus not needed");
     return;
   }
   var winnus = undefined;
   try {
     winnus = require('winnus');
   } catch (e) {
-    console.log("'winnus' module not found, no Windows Bluetooth Low Energy", e);
+    logger.debug("'winnus' module not found, no Windows Bluetooth Low Energy", e);
     return;
   }
-  console.log("Disable Web Bluetooth as we have Winnus instead");
+  logger.debug("Disable Web Bluetooth as we have Winnus instead");
   Espruino.Core.Serial.NO_WEB_BLUETOOTH = true;
 
   var txDataQueue = undefined;
@@ -30,7 +30,7 @@
         devices.push({ description : dev.name, path: dev.address, type : "bluetooth" });
       });
     } catch (e) {
-      console.log(e);
+      logger.error(e);
     }
     callback(devices, false/*instantPorts*/);
   };
@@ -64,7 +64,7 @@
     try {
       winnus.disconnect();
     } catch (e) {
-      console.log("WINNUS ERROR:"+e.toString());
+      logger.error("WINNUS ERROR:"+e.toString());
     }
     if (onDisconnect) {
       onDisconnect();
@@ -94,7 +94,7 @@
         txDataQueue = txDataQueue.substr(CHUNKSIZE);
       }
       txInProgress = true;
-      console.log("BT> Sending " + JSON.stringify(chunk));
+      logger.debug("BT> Sending " + JSON.stringify(chunk));
       try {
         winnus.write(chunk);
         setTimeout(function() {
@@ -103,7 +103,7 @@
             writeChunk();
         }, 20);
       } catch (e) {
-        console.log("BT> ERROR " + e);
+        logger.error("BT> ERROR " + e);
         txDataQueue = undefined;
       }
     }
diff --git a/core/terminal.js b/core/terminal.js
index faed51c..09814f8 100644
--- a/core/terminal.js
+++ b/core/terminal.js
@@ -53,7 +53,7 @@
     var terminal = document.getElementById("terminal");
     var terminalfocus = document.getElementById("terminalfocus");
     if (terminal === null) {
-      console.log("Terminal: terminal element not found, aborting.");
+      logger.error("Terminal: terminal element not found, aborting.");
       delete Espruino.Core.Terminal;
       return;
     }
@@ -523,7 +523,7 @@
        if (termControlChars[2]==63) {
          if (termControlChars[3]==55) {
            if (ch!=108)
-             console.log("Expected 27, 91, 63, 55, 108 - no line overflow sequence");
+             logger.warn("Expected 27, 91, 63, 55, 108 - no line overflow sequence");
            termControlChars = [];
          } else {
            if (ch==55) {
@@ -697,7 +697,7 @@
     updateTerminal();
     if (options.buttonclick) {
       var btn = elements[line].find("button");
-      if (!btn.length) console.error("Espruino.Core.Terminal buttonclick set but no button");
+      if (!btn.length) logger.error("Espruino.Core.Terminal buttonclick set but no button");
       btn.on('click', options.buttonclick);
     }
   }
diff --git a/core/utils.js b/core/utils.js
index cbfbd1a..561bfee 100644
--- a/core/utils.js
+++ b/core/utils.js
@@ -236,7 +236,7 @@
   function getEspruinoPrompt(callback) {
     if (Espruino.Core.Terminal!==undefined &&
         Espruino.Core.Terminal.getTerminalLine()==">") {
-      console.log("Found a prompt... great!");
+      logger.debug("Found a prompt... great!");
       return callback();
     }
 
@@ -248,13 +248,13 @@
       }
       if (receivedData[receivedData.length-1] == ">") {
         if (receivedData.substr(-6)=="debug>") {
-          console.log("Got debug> - sending Ctrl-C to break out and we'll be good");
+          logger.debug("Got debug> - sending Ctrl-C to break out and we'll be good");
           Espruino.Core.Serial.write('\x03');
         } else {
           if (receivedData == "\r\n=undefined\r\n>")
             receivedData=""; // this was just what we expected - so ignore it
 
-          console.log("Received a prompt after sending newline... good!");
+          logger.debug("Received a prompt after sending newline... good!");
           clearTimeout(timeout);
           nextStep();
         }
@@ -263,13 +263,13 @@
     // timeout in case something goes wrong...
     var hadToBreak = false;
     var timeout = setTimeout(function() {
-      console.log("Got "+JSON.stringify(receivedData));
+      logger.error("Got "+JSON.stringify(receivedData));
       // if we haven't had the prompt displayed for us, Ctrl-C to break out of what we had
-      console.log("No Prompt found, got "+JSON.stringify(receivedData[receivedData.length-1])+" - issuing Ctrl-C to try and break out");
+      logger.error("No Prompt found, got "+JSON.stringify(receivedData[receivedData.length-1])+" - issuing Ctrl-C to try and break out");
       Espruino.Core.Serial.write('\x03');
       hadToBreak = true;
       timeout = setTimeout(function() {
-        console.log("Still no prompt - issuing another Ctrl-C");
+        logger.error("Still no prompt - issuing another Ctrl-C");
         Espruino.Core.Serial.write('\x03');
         nextStep();
       },500);
@@ -324,7 +324,7 @@
         if(startProcess >= 0 && endProcess > 0){
           // All good - get the data!
           var result = receivedData.substring(startProcess + 4,endProcess);
-          console.log("Got "+JSON.stringify(receivedData));
+          logger.debug("Got "+JSON.stringify(receivedData));
           // strip out the text we found
           receivedData = receivedData.substr(0,startProcess) + receivedData.substr(endProcess+4);
           // Now stop time timeout
@@ -375,7 +375,7 @@
               // No data yet...
               // OR we keep getting data for > options.maxTimeout seconds
               clearInterval(timeout);
-              console.warn("No result found for "+JSON.stringify(expressionToExecute)+" - just got "+JSON.stringify(receivedData));
+              logger.warn("No result found for "+JSON.stringify(expressionToExecute)+" - just got "+JSON.stringify(receivedData));
               nextStep(undefined);
             }
           }, pollInterval);
@@ -388,7 +388,7 @@
         getProcessInfo(expressionToExecute, callback);
       });
     } else {
-      console.error("executeExpression called when not connected!");
+      logger.error("executeExpression called when not connected!");
       callback(undefined);
     }
   };
@@ -447,12 +447,12 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
             if (xhr.status === 200) {
               callback(xhr.response.toString());
             } else {
-              console.error("getURL("+JSON.stringify(url)+") error : HTTP "+xhr.status);
+              logger.error("getURL("+JSON.stringify(url)+") error : HTTP "+xhr.status);
               callback(undefined);
             }
           });
           xhr.addEventListener("error", function (e) {
-            console.error("getURL("+JSON.stringify(url)+") error "+e);
+            logger.error("getURL("+JSON.stringify(url)+") error "+e);
             callback(undefined);
           });
           xhr.open("GET", url, true);
@@ -470,7 +470,7 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
 
             require(m).get(http_options, function(res) {
               if (res.statusCode != 200) {
-                console.log("Espruino.Core.Utils.getURL: got HTTP status code "+res.statusCode+" for "+url);
+                logger.debug("Espruino.Core.Utils.getURL: got HTTP status code "+res.statusCode+" for "+url);
                 return callback(undefined);
               }
               var data = "";
@@ -479,13 +479,13 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
                 callback(data);
               });
             }).on('error', function(err) {
-              console.error("getURL("+JSON.stringify(url)+") error : "+err);
+              logger.error("getURL("+JSON.stringify(url)+") error : "+err);
               callback(undefined);
             });
           } else {
             require("fs").readFile(resultUrl, function(err, d) {
               if (err) {
-                console.error(err);
+                logger.error(err);
                 callback(undefined);
               } else
                 callback(d.toString());
@@ -498,7 +498,7 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
 
   /// Gets a URL as a Binary file, returning callback(err, ArrayBuffer)
   var getBinaryURL = function(url, callback) {
-    console.log("Downloading "+url);
+    logger.debug("Downloading "+url);
     Espruino.Core.Status.setStatus("Downloading binary...");
     var xhr = new XMLHttpRequest();
     xhr.responseType = "arraybuffer";
@@ -522,7 +522,7 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
     getURL(url, function(d) {
       if (!d) return callback(d);
       var j;
-      try { j=JSON.parse(d); } catch (e) { console.error("Unable to parse JSON",d); }
+      try { j=JSON.parse(d); } catch (e) { logger.error("Unable to parse JSON",d); }
       callback(j);
     });
   }
@@ -629,14 +629,14 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
           // when truncation has finished, write
           writer.onwriteend = function(e) {
             writer.onwriteend = function(e) {
-              console.log('FileWriter: complete');
+              logger.debug('FileWriter: complete');
               if (callback) callback(writableFileEntry.name);
             };
-            console.log('FileWriter: writing');
+            logger.debug('FileWriter: writing');
             writer.write(fileBlob);
           };
           // truncate
-          console.log('FileWriter: truncating');
+          logger.debug('FileWriter: truncating');
           writer.truncate(fileBlob.size);
         }, errorHandler);
       });
@@ -702,7 +702,7 @@ while (d!==undefined) {console.log(btoa(d));d=f.read(${CHUNKSIZE});}
     for (var i=0; i<str.length; i++) {
       var ch = str.charCodeAt(i);
       if (ch>=256) {
-        console.warn("stringToArrayBuffer got non-8 bit character - code "+ch);
+        logger.warn("stringToArrayBuffer got non-8 bit character - code "+ch);
         ch = "?".charCodeAt(0);
       }
       buf[i] = ch;
diff --git a/espruino.js b/espruino.js
index 31dc195..178287c 100644
--- a/espruino.js
+++ b/espruino.js
@@ -45,12 +45,12 @@ var Espruino;
     Espruino.Core.Config.loadConfiguration(function() {
       // Initialise all modules
       function initModule(modName, mod) {
-        console.log("Initialising "+modName);
+        logger.debug("Initialising "+modName);
         if (mod.init !== undefined) {
           try {
             mod.init();
           } catch (e) {
-            console.warn("Module initialisation failed for "+modName, e);
+            logger.warn("Module initialisation failed for "+modName, e);
           }
         }
       }
diff --git a/index.js b/index.js
index b3096bd..d3b2207 100644
--- a/index.js
+++ b/index.js
@@ -2,10 +2,17 @@ require('es6-shim');
 /* Entrypoint for node module. Not used for Web IDE */
 var fs = require("fs");
 
+var espruinoInitialised = false;
+var logger;
+var defaultOptions = {
+  logLevel: 3
+};
+var storedOptions = Object.assign({}, defaultOptions);
+
 /* load all files in EspruinoTools... we do this so we can still
 use these files normally in the Web IDE */
 function loadJS(filePath) {
-  console.log("Found "+filePath);
+  logger.debug("Found "+filePath);
   var contents = fs.readFileSync(filePath, {encoding:"utf8"});
   var realExports = exports;
   exports = undefined;
@@ -46,11 +53,60 @@ var jqShim = {
 };
 // ---------------
 
-var espruinoInitialised = false;
+function createLogger(logLevel) {
+  var getFunc = function getFunc(type, method) {
+    var shouldLog = function() {
+      if (!logLevel && logLevel !== 0) {
+        logLevel = defaultOptions.logLevel;
+      }
+      if (logLevel >= 0 && type === 'error') return true;
+      if (logLevel >= 1 && type === 'log') return true;
+      if (logLevel >= 2 && type === 'warn') return true;
+      if (logLevel >= 3 && type === 'debug') return true;
+      return false;
+    };
+    return function () {
+      if (shouldLog()) {
+        console[method || type].apply(console, arguments);
+      }
+    };
+  };
+  return {
+    error: getFunc('error'),
+    log: getFunc('log'),
+    warn: getFunc('warn'),
+    debug: getFunc('debug', 'log')
+  };
+};
+
+function handleInitArguments(arg1, arg2) {
+  var callback;
+  var opts;
+  if (typeof arg1 === 'function') {
+    callback = arg1;
+  } else if (typeof arg2 === 'function') {
+    callback = arg2;
+  }
+  if (typeof arg1 === 'object') {
+    opts = arg1;
+  } else if (espruinoInitialised) {
+    opts = storedOptions;
+  }
+  storedOptions = Object.assign({}, defaultOptions, storedOptions, opts);
+  return {
+    callback: callback,
+    options: storedOptions
+  };
+};
+
+function init(options, callback) {
+  var handled = handleInitArguments(options, callback);
+  options = handled.options;
+  callback = handled.callback;
+  logger = logger || createLogger(options.logLevel);
 
-function init(callback) {
   if (espruinoInitialised) {
-    console.log("Already initialised.");
+    logger.debug("Already initialised.");
     return callback();
   }
   espruinoInitialised = true;
@@ -69,7 +125,7 @@ function init(callback) {
     global.acorn = require("acorn");
     acorn.walk = require("acorn/util/walk"); // FIXME - Package subpath './util/walk' is not defined by "exports" in latest 
   } catch(e) {
-    console.log("Acorn library not found - you'll need it for compiled code");
+    logger.warn("Acorn library not found - you'll need it for compiled code");
   }
 
   // Load each JS file...
@@ -85,13 +141,13 @@ function init(callback) {
 
   // Bodge up notifications
   Espruino.Core.Notifications = {
-    success : function(e) { console.log(e); },
-    error : function(e) { console.error(e); },
-    warning : function(e) { console.warn(e); },
-    info : function(e) { console.log(e); },
+    success : function(e) { logger.debug(e); },
+    error : function(e) { logger.error(e); },
+    warning : function(e) { logger.warn(e); },
+    info : function(e) { logger.debug(e); },
   };
   Espruino.Core.Status = {
-    setStatus : function(e,len) { console.log(e); },
+    setStatus : function(e,len) { logger.debug(e); },
     hasProgress : function() { return false; },
     incrementProgress : function(amt) {}
   };
@@ -125,7 +181,7 @@ function sendCode(port, code, callback) {
      });
     Espruino.Core.Serial.open(port, function(status) {
       if (status === undefined) {
-        console.error("Unable to connect!");
+        logger.error("Unable to connect!");
         return callback();
       }
       Espruino.callProcessor("transformForEspruino", code, function(code) {
@@ -149,7 +205,7 @@ exports.expr = function(port, expr, callback) {
     Espruino.Core.Serial.startListening(function(data) { });
     Espruino.Core.Serial.open(port, function(status) {
       if (status === undefined) {
-        console.error("Unable to connect!");
+        logger.error("Unable to connect!");
         return callback();
       }
       Espruino.Core.Utils.executeExpression(expr, function(result) {
@@ -171,7 +227,7 @@ exports.statement = function(port, expr, callback) {
     Espruino.Core.Serial.startListening(function(data) { });
     Espruino.Core.Serial.open(port, function(status) {
       if (status === undefined) {
-        console.error("Unable to connect!");
+        logger.error("Unable to connect!");
         return callback();
       }
       Espruino.Core.Utils.executeStatement(expr, function(result) {
@@ -199,13 +255,13 @@ exports.flash = function(port, filename, flashOffset, callback) {
     Espruino.Core.Serial.startListening(function(data) { });
     Espruino.Core.Serial.open(port, function(status) {
       if (status === undefined) {
-        console.error("Unable to connect!");
+        logger.error("Unable to connect!");
         return callback();
       }
       var bin = fs.readFileSync(filename, {encoding:"binary"});
       Espruino.Core.Flasher.flashBinaryToDevice(bin, flashOffset, function(err) {
-        console.log(err ? "Error!" : "Success!");
-        setTimeout(function() {
+        logger[err ? 'error' : 'log'](err ? "Error!" : "Success!");
+        setTimeout(function () {
           Espruino.Core.Serial.close();
         }, 500);
       });
diff --git a/libs/esprima/esmangle.js b/libs/esprima/esmangle.js
index 6283f4b..bf05006 100644
--- a/libs/esprima/esmangle.js
+++ b/libs/esprima/esmangle.js
@@ -6980,7 +6980,7 @@ exports.deprecate = function(fn, msg) {
       } else if (process.traceDeprecation) {
         console.trace(msg);
       } else {
-        console.error(msg);
+        logger.error(msg);
       }
       warned = true;
     }
@@ -7002,7 +7002,7 @@ exports.debuglog = function(set) {
       var pid = process.pid;
       debugs[set] = function() {
         var msg = exports.format.apply(exports, arguments);
-        console.error('%s %d: %s', set, pid, msg);
+        logger.error('%s %d: %s', set, pid, msg);
       };
     } else {
       debugs[set] = function() {};
@@ -7446,9 +7446,9 @@ function timestamp() {
 }
 
 
-// log is just a thin wrapper to console.log that prepends a timestamp
+// log is just a thin wrapper to logger.debug that prepends a timestamp
 exports.log = function() {
-  console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
+  logger.debug('%s - %s', timestamp(), exports.format.apply(exports, arguments));
 };
 
 
diff --git a/plugins/assembler.js b/plugins/assembler.js
index e97040a..ab5033e 100644
--- a/plugins/assembler.js
+++ b/plugins/assembler.js
@@ -362,7 +362,7 @@
     });
     // process assembly to grab labels
     var labels = assemble_internal(asmLines, function() {}, undefined);
-    console.log("Assembler Labels:",labels);
+    logger.debug("Assembler Labels:",labels);
     // process again to actually get an output
     assemble_internal(asmLines, wordCallback, labels);
   }
@@ -390,7 +390,7 @@
     try {
       assemble(asmLines, function(word) { machineCode.push("0x"+word.toString(16)); });
     } catch (err) {
-      console.log("Assembler failed: "+err+description);
+      logger.error("Assembler failed: "+err+description);
       Espruino.Core.Notifications.error("Assembler failed: "+err+description);
       return undefined;
     }
diff --git a/plugins/boardJSON.js b/plugins/boardJSON.js
index c0f3d5c..20c16b0 100644
--- a/plugins/boardJSON.js
+++ b/plugins/boardJSON.js
@@ -32,9 +32,9 @@
   }
   
   function loadJSON(env, jsonPath, callback) {    
-    console.log("Loading "+jsonPath);
+    logger.debug("Loading "+jsonPath);
     Espruino.Core.Utils.getJSONURL(jsonPath, function(data){
-      console.log("Board JSON loaded");
+      logger.debug("Board JSON loaded");
       for (var key in data)
         env[key] = data[key];
       Espruino.callProcessor("boardJSONLoaded", env, callback);          
diff --git a/plugins/compiler.js b/plugins/compiler.js
index 47e0052..5118481 100644
--- a/plugins/compiler.js
+++ b/plugins/compiler.js
@@ -147,7 +147,7 @@
       });
 
     } catch (err) {
-      console.log(err);
+      logger.error(err);
       Espruino.Core.Notifications.error("Error parsing JavaScript"+description+", but uploading anyway.<br/>"+err.toString());
     }
     if (tasks==0)
diff --git a/plugins/getGitHub.js b/plugins/getGitHub.js
index d9f3e85..9bd414f 100644
--- a/plugins/getGitHub.js
+++ b/plugins/getGitHub.js
@@ -27,7 +27,7 @@
           };
       
       var url = "https://raw.githubusercontent.com/"+git.owner+"/"+git.repo+"/"+git.branch+"/"+git.path;
-      console.log("Found GitHub", JSON.stringify(git));
+      logger.debug("Found GitHub", JSON.stringify(git));
       callback({url: url});
     } else
       callback(data); // no match - continue as normal
diff --git a/plugins/localModules.js b/plugins/localModules.js
index c406fc5..77ae1c6 100644
--- a/plugins/localModules.js
+++ b/plugins/localModules.js
@@ -40,14 +40,14 @@
          *
          */
         function loadJSFile(x) {
-            console.log("Loading local module "+ x +" for " + data.moduleName);
+            logger.debug("Loading local module "+ x +" for " + data.moduleName);
             data.moduleCode = fs.readFileSync(x).toString();
             return true;
         }
 
         function loadJSONFile(x) {
-            console.log("Loading local module "+ x +" for " + data.moduleName);
-            console.log('module.exports=' + JSON.stringify(JSON.parse(fs.readFileSync(x).toString())) + ';');
+            logger.debug("Loading local module "+ x +" for " + data.moduleName);
+            logger.debug('module.exports=' + JSON.stringify(JSON.parse(fs.readFileSync(x).toString())) + ';');
             data.moduleCode = 'module.exports=' + JSON.stringify(JSON.parse(fs.readFileSync(x).toString())) + ';';
             return true;
         }
diff --git a/plugins/minify.js b/plugins/minify.js
index 5f70308..8ed28ef 100644
--- a/plugins/minify.js
+++ b/plugins/minify.js
@@ -74,7 +74,7 @@
     if ((typeof esprima == "undefined") ||
         (typeof esmangle == "undefined") ||
         (typeof escodegen == "undefined")) {
-      console.warn("esprima/esmangle/escodegen not defined - not minifying")
+      logger.warn("esprima/esmangle/escodegen not defined - not minifying")
       return callback(code);
     }
 
@@ -106,7 +106,7 @@
         callback(code);
     } catch (e) {
       Espruino.Core.Notifications.error(e.toString()+description);
-      console.error(e.stack);
+      logger.error(e.stack);
       callback(code);
     } finally { }
   }
@@ -131,7 +131,7 @@
     for (var i in minifyCache) {
       var item = minifyCache[i];
       if (item.code==code && item.level==minificationLevel) {
-        console.log("Found code in minification cache - using that"+description);
+        logger.debug("Found code in minification cache - using that"+description);
         // move to front of cache
         minifyCache.splice(i,1); // remove old
         minifyCache.push(item); // add at front
diff --git a/plugins/pretokenise.js b/plugins/pretokenise.js
index 8a7903b..5da8df3 100644
--- a/plugins/pretokenise.js
+++ b/plugins/pretokenise.js
@@ -12,7 +12,7 @@
 "use strict";
 (function(){
   if (typeof acorn == "undefined") {
-    console.log("pretokenise: needs acorn, disabling.");
+    logger.debug("pretokenise: needs acorn, disabling.");
     return;
   }
 
diff --git a/plugins/saveOnSend.js b/plugins/saveOnSend.js
index 9cb6baf..364e33d 100644
--- a/plugins/saveOnSend.js
+++ b/plugins/saveOnSend.js
@@ -71,7 +71,7 @@
     }
 
     //
-    console.log("Uploading "+code.length+" bytes to flash");
+    logger.debug("Uploading "+code.length+" bytes to flash");
     if (!hasStorage) { // old style
       if (isStorageUpload) {
         Espruino.Core.Notifications.error("You have pre-1v96 firmware - unable to upload to Storage");
diff --git a/plugins/unicode.js b/plugins/unicode.js
index 67d1a1b..4012712 100644
--- a/plugins/unicode.js
+++ b/plugins/unicode.js
@@ -17,14 +17,14 @@
   var utf8lib;
   if ("undefined"==typeof utf8) {
     if ("undefined"!=typeof require) {
-      console.log("Loading UTF8 with require");
+      logger.debug("Loading UTF8 with require");
       utf8lib = require('utf8');
     } else {
-      console.log("WARNING: Loading placeholder UTF8");
+      logger.warn("WARNING: Loading placeholder UTF8");
       utf8lib = { encode : function(c){return c} };
     }
   } else {
-    console.log("UTF8 Library loaded successfully");
+    logger.debug("UTF8 Library loaded successfully");
     utf8lib = utf8;
   }
 
diff --git a/plugins/versionChecker.js b/plugins/versionChecker.js
index 09bebd8..dd59c0a 100644
--- a/plugins/versionChecker.js
+++ b/plugins/versionChecker.js
@@ -58,7 +58,7 @@
 
       if (vCurrent > 1.43 &&
           (env.CONSOLE=="USB"||env.CONSOLE=="Bluetooth"||env.CONSOLE=="Telnet")) {
-        console.log("Firmware >1.43 supports faster writes over USB");
+        logger.debug("Firmware >1.43 supports faster writes over USB");
         Espruino.Core.Serial.setSlowWrite(false);
       } else {
         Espruino.Core.Serial.setSlowWrite(true);
@@ -69,14 +69,14 @@
         var tAvailable = env.info.binary_version;
         var vAvailable = Espruino.Core.Utils.versionToFloat(tAvailable);
 
-        console.log("FIRMWARE: Current "+tCurrent+", Available "+tAvailable);
+        logger.debug("FIRMWARE: Current "+tCurrent+", Available "+tAvailable);
 
         if (vAvailable > vCurrent &&
           (env.BOARD=="ESPRUINOBOARD" ||
            env.BOARD.substr(0,4)=="PICO" ||
            env.BOARD=="ESPRUINOWIFI" ||
            env.BOARD=="PUCKJS")) {
-          console.log("New Firmware "+tAvailable+" available");
+          logger.debug("New Firmware "+tAvailable+" available");
           Espruino.Core.Notifications.info("New Firmware available ("+vCurrent+" installed, "+tAvailable+" available)");
 
           if (Espruino.Core.App) Espruino.Core.App.addAlertIcon({