diff --git a/PyMca5/PyMcaIO/TiffIO.py b/PyMca5/PyMcaIO/TiffIO.py
index 6ddb7634b..ff455f68a 100644
--- a/PyMca5/PyMcaIO/TiffIO.py
+++ b/PyMca5/PyMcaIO/TiffIO.py
@@ -30,7 +30,7 @@
 __contact__ = "sole@esrf.fr"
 __license__ = "MIT"
 __copyright__ = "European Synchrotron Radiation Facility, Grenoble, France"
-__date__ = "16/12/2022"
+__date__ = "25/10/2023"
 
 import sys
 import os
@@ -143,13 +143,13 @@ def _initInternalVariables(self, fd=None):
             self.fd = fd
         # read the order
         fd.seek(0)
-        order = fd.read(2).decode()
+        order = fd.read(2)
         if len(order):
-            if order == "II":
+            if order == b"II":
                 # intel, little endian
                 fileOrder = "little"
                 self._structChar = '<'
-            elif order == "MM":
+            elif order == b"MM":
                 # motorola, high endian
                 fileOrder = "big"
                 self._structChar = '>'