diff --git a/kernel_fetcher.sh b/kernel_fetcher.sh
index 166fe59158..e85566a8b5 100755
--- a/kernel_fetcher.sh
+++ b/kernel_fetcher.sh
@@ -47,7 +47,7 @@ trap do_cleanup EXIT
 #
 echo "Fetching kernel from root image..."
 mkdir /tmp/kernel_fetch.$$
-sudo mount -o loop "${FLAGS_from}/rootfs.image" /tmp/kernel_fetch.$$
+sudo mount -o ro,loop "${FLAGS_from}/rootfs.image" /tmp/kernel_fetch.$$
 
 echo "Writing kernel to ${FLAGS_to} at ${FLAGS_offset}..."
 sudo "${SCRIPTS_DIR}"/file_copy.py \