diff --git a/lib/tiny-cloud/nocloud/imds b/lib/tiny-cloud/nocloud/imds
index 9d7b7df..a841bb0 100644
--- a/lib/tiny-cloud/nocloud/imds
+++ b/lib/tiny-cloud/nocloud/imds
@@ -54,7 +54,7 @@ _load_nocloud_volume() {
         [ "$mounted" ] && break
         for label in cidata CIDATA; do
             [ -n "$mounted" ] && break
-            mount -t "$fstype" LABEL="$label" "$mntdir" && mounted=1
+            mount -o ro -t "$fstype" LABEL="$label" "$mntdir" && mounted=1
         done
     done
     if [ -n "$mounted" ]; then