diff --git a/files/initramfs-tools/union-mount.j2 b/files/initramfs-tools/union-mount.j2
index c680e69300..7a64f71d70 100644
--- a/files/initramfs-tools/union-mount.j2
+++ b/files/initramfs-tools/union-mount.j2
@@ -132,7 +132,7 @@ case "${ROOT}" in
         ;;
     *)
         ## Mount the raw partition again
-        mount ${ROOT} ${rootmnt}/host
+        mount -t ext4 ${ROOT} ${rootmnt}/host
         ;;
 esac