[TEST - REMOVE] Pack only one module for easier development

Signed-off-by: Alex Gonzalez <alexg@balena.io>

Author: alexgg

layers/meta-kernel-modules-block/recipes-core/images/balena-kernel-modules-block.bb

@@ -23,6 +23,21 @@ remove_unnecessary_files() {
 
     # Remove run directory
     rm -rf ${IMAGE_ROOTFS}/run
+
+    # DEBUG: Keep only a single harmless module (btrfs) to test overlay mechanism
+    # This helps isolate whether boot failure is due to overlay or module contents
+    modulesdir="${IMAGE_ROOTFS}/usr/lib/modules"
+    if [ -d "${modulesdir}" ]; then
+        # Find and keep only btrfs.ko (unlikely to auto-load, harmless)
+        find "${modulesdir}" -name "*.ko*" ! -name "btrfs.ko*" -delete
+        # Remove empty directories
+        find "${modulesdir}" -type d -empty -delete
+        # Regenerate modules.dep for the single module
+        kernelver=$(ls "${modulesdir}" | head -1)
+        if [ -n "${kernelver}" ]; then
+            depmod -b "${IMAGE_ROOTFS}/usr" "${kernelver}" || true
+        fi
+    fi
 }
 
 IMAGE_PREPROCESS_COMMAND += "remove_unnecessary_files;"