diff --git a/stage4/prerun.sh b/stage4/prerun.sh
new file mode 100644
index 00000000..9acd13cb
--- /dev/null
+++ b/stage4/prerun.sh
@@ -0,0 +1,5 @@
+#!/bin/bash -e
+
+if [ ! -d "${ROOTFS_DIR}" ]; then
+	copy_previous
+fi