diff --git a/docker/base/setup_clusterfuzz.sh b/docker/base/setup_clusterfuzz.sh
index ec67c0f041f..96a770ac8d8 100644
--- a/docker/base/setup_clusterfuzz.sh
+++ b/docker/base/setup_clusterfuzz.sh
@@ -28,6 +28,7 @@ fi
 
 if [[ "$IMMUTABLE_IMAGE" == "true" ]]; then
   echo "Not downloading Clusterfuzz source code as it is an immutable image"
+  ln -s /data/clusterfuzz $INSTALL_DIRECTORY/
 else
   CLUSTERFUZZ_FILE=clusterfuzz_package.zip
   # When $LOCAL_SRC is set, use source zip on mounted volume for local testing.
diff --git a/docker/build-immutable.sh b/docker/build-immutable.sh
index d91ea2414be..ddbf17a3230 100755
--- a/docker/build-immutable.sh
+++ b/docker/build-immutable.sh
@@ -50,9 +50,9 @@ rm -rf src/appengine/config
 
 # Loop through each image name in the IMAGES array.
 for image_name in "${IMAGES[@]}"; do
-  # Read the ClusterFuzz revision from the revision.txt file. This is used to
+  # Read the ClusterFuzz revision from the clusterfuzz-source.manifest file. This is used to
   # tag the Docker images.
-  CURRENT_CLUSTERFUZZ_REVISION="$(cat /workspace/revision.txt)"
+  CURRENT_CLUSTERFUZZ_REVISION="$(cat src/appengine/resources/clusterfuzz-source.manifest)"
 
   # Determine the directory containing the Dockerfile and related build context.
   project_dir=docker/${image_name#gcr.io/clusterfuzz-images/}
diff --git a/docker/immutable-cloudbuild.yaml b/docker/immutable-cloudbuild.yaml
index 2823321bfa4..66fb17c51aa 100644
--- a/docker/immutable-cloudbuild.yaml
+++ b/docker/immutable-cloudbuild.yaml
@@ -52,6 +52,7 @@ steps:
       git clone https://github.com/google/clusterfuzz.git
       cd clusterfuzz
       git checkout "${_CLUSTERFUZZ_REVISION}"
+      cp -r /workspace/clusterfuzz-config .
     else
       echo "☑️ _CLUSTERFUZZ_REVISION is not set. Using the latest commit."
     fi
@@ -74,11 +75,11 @@ steps:
     
     # Using the builder service account as the user
     RAW_USER=$(gcloud auth list --filter=status:ACTIVE --format="value(account)")
-    USER=$(echo "$$RAW_USER" | cut -d'@' -f1)
+    USER=$(echo "$$RAW_USER" | cut -d'@' -f1 | sed 's/-compute//')
     
     REVISION="$${TIMESTAMP}-$${CF_SHA}-$${USER}-$${CF_CONFIG_SHA}-prod"
     echo "Computed revision: $${REVISION}"
-    echo "$${REVISION}" > /workspace/revision.txt
+    echo "$${REVISION}" > src/appengine/resources/clusterfuzz-source.manifest
 
 - id: build immutable image
   name: gcr.io/cloud-builders/docker
diff --git a/src/clusterfuzz/_internal/system/environment.py b/src/clusterfuzz/_internal/system/environment.py
index 6618a011907..6b37b662978 100644
--- a/src/clusterfuzz/_internal/system/environment.py
+++ b/src/clusterfuzz/_internal/system/environment.py
@@ -1195,6 +1195,10 @@ def is_tworker():
   return get_value('TWORKER', False)
 
 
+def is_immutable_instance():
+  return get_value('IMMUTABLE_IMAGE', False)
+
+
 def update_task_enabled() -> bool:
   """ It uses the GCE VM metadata server `update_task_enabled` flag.
 
diff --git a/src/python/bot/startup/run.py b/src/python/bot/startup/run.py
index 0cd1a07cc2b..7e031b0734b 100644
--- a/src/python/bot/startup/run.py
+++ b/src/python/bot/startup/run.py
@@ -173,6 +173,9 @@ def stop_android_heartbeat():
 
 def update_source_code_if_needed():
   """Update source code if needed."""
+  if environment.is_immutable_instance():
+    logs.info("This is an immutable image, not updating source code.")
+    return
   try:
     # Update the bot source, if there's a newer version.
     newer_source_revision = update_task.get_newer_source_revision()