diff --git a/sw/host/opentitantool/BUILD b/sw/host/opentitantool/BUILD
index 958f698d48b12..0f5089f8187a1 100644
--- a/sw/host/opentitantool/BUILD
+++ b/sw/host/opentitantool/BUILD
@@ -43,7 +43,7 @@ rust_binary(
         "stamp-env.txt",
     ],
     # stamping is necessary because opentitantool builds version.rs that needs it
-    stamp = 1,
+    stamp = -1,
     deps = [
         "//sw/host/opentitanlib",
         "//sw/host/ot_certs",
diff --git a/sw/host/opentitantool/src/command/gpio.rs b/sw/host/opentitantool/src/command/gpio.rs
index eaafeaafb15a4..4f0b27e9df8b1 100644
--- a/sw/host/opentitantool/src/command/gpio.rs
+++ b/sw/host/opentitantool/src/command/gpio.rs
@@ -410,10 +410,17 @@ impl CommandDispatch for GpioMonitoringVcd {
         let version = super::version::VersionResponse::default();
         writeln!(
             &mut file,
-            "   opentitantool {} {} {}",
-            version.version,
-            if version.clean { "clean" } else { "modified" },
-            version.timestamp,
+            "   opentitantool {} {}",
+            version.version.unwrap_or("<unknown>".into()),
+            if let Some(clean) = version.clean {
+                if clean {
+                    "clean"
+                } else {
+                    "modified"
+                }
+            } else {
+                "<unknown>"
+            }
         )?;
         writeln!(&mut file, "$end")?;
         match clock_nature {
diff --git a/sw/host/opentitantool/src/command/version.rs b/sw/host/opentitantool/src/command/version.rs
index 71a5e2477c5a1..8a88d7ece7cd2 100644
--- a/sw/host/opentitantool/src/command/version.rs
+++ b/sw/host/opentitantool/src/command/version.rs
@@ -15,19 +15,29 @@ pub struct Version {}
 
 #[derive(Debug, serde::Serialize)]
 pub struct VersionResponse {
-    pub version: String,
-    pub revision: String,
-    pub clean: bool,
-    pub timestamp: i64,
+    pub version: Option<String>,
+    pub revision: Option<String>,
+    pub clean: Option<bool>,
+}
+
+fn parse_variable(content: &str) -> Option<String> {
+    // If stamping is disabled, the variable substition in stamp-env.txt
+    // will not happen and the content of the environment variable will be
+    // `{NAME_OF_VARIABLE}`. If we detect that this is the case, we return
+    // None, otherwise we return the content.
+    if content.starts_with('{') {
+        None
+    } else {
+        Some(content.to_string())
+    }
 }
 
 impl Default for VersionResponse {
     fn default() -> Self {
         VersionResponse {
-            version: std::env!("BUILD_GIT_VERSION").to_string(),
-            revision: std::env!("BUILD_SCM_REVISION").to_string(),
-            clean: std::env!("BUILD_SCM_STATUS") == "clean",
-            timestamp: std::env!("BUILD_TIMESTAMP").parse::<i64>().unwrap(),
+            version: parse_variable(std::env!("BUILD_GIT_VERSION")),
+            revision: parse_variable(std::env!("BUILD_SCM_REVISION")),
+            clean: parse_variable(std::env!("BUILD_SCM_STATUS")).map(|x| x == "clean"),
         }
     }
 }