diff --git a/crates/openshell-driver-vm/scripts/openshell-vm-sandbox-init.sh b/crates/openshell-driver-vm/scripts/openshell-vm-sandbox-init.sh
index 2166e06177..906d27bb1d 100644
--- a/crates/openshell-driver-vm/scripts/openshell-vm-sandbox-init.sh
+++ b/crates/openshell-driver-vm/scripts/openshell-vm-sandbox-init.sh
@@ -243,6 +243,12 @@ setup_overlay_root() {
     if [ "${OPENSHELL_VM_INIT_MODE:-sandbox}" = "image-prep" ]; then
         prepare_guest_image_rootfs
         sync
+        if mount -o remount,ro /overlay 2>/dev/null; then
+            :
+        else
+            umount /overlay
+        fi
+        sync
         ts "image-prep complete"
         exit 0
     fi
@@ -252,7 +258,7 @@ setup_overlay_root() {
 
     local lower_root="/lower"
     if [ -b /dev/vdc ]; then
-        mount -t ext4 -o ro /dev/vdc /image-cache
+        mount -t ext4 -o ro,noload /dev/vdc /image-cache
         if [ -d /image-cache/image-rootfs ]; then
             lower_root="/image-cache/image-rootfs"
             ts "using prepared image rootfs lowerdir"
diff --git a/crates/openshell-driver-vm/src/runtime.rs b/crates/openshell-driver-vm/src/runtime.rs
index a6ddfe011d..65b2753ce4 100644
--- a/crates/openshell-driver-vm/src/runtime.rs
+++ b/crates/openshell-driver-vm/src/runtime.rs
@@ -1057,7 +1057,12 @@ impl VmContext {
                         self.ctx_id,
                         image_block_id_c.as_ptr(),
                         image_disk_c.as_ptr(),
-                        true,
+                        // Attach as writable at the hypervisor level so the
+                        // kernel can replay the ext4 journal if the image-prep
+                        // VM did not unmount cleanly. The guest still mounts
+                        // the filesystem with -o ro, so guest processes cannot
+                        // write to it. See: openshell-vm-sandbox-init.sh
+                        false,
                     )
                 },
                 "krun_add_disk",