diff --git a/target/linux/apm821xx/image/mbl_gen_hdd_img.sh b/target/linux/apm821xx/image/mbl_gen_hdd_img.sh
index 1fb868b5b3..0e11e10226 100755
--- a/target/linux/apm821xx/image/mbl_gen_hdd_img.sh
+++ b/target/linux/apm821xx/image/mbl_gen_hdd_img.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 set -x
 [ $# -eq 5 ] || {