diff --git a/files/initrd/opt/arc/arc.sh b/files/initrd/opt/arc/arc.sh
index 06f52140..a0992e1e 100755
--- a/files/initrd/opt/arc/arc.sh
+++ b/files/initrd/opt/arc/arc.sh
@@ -2378,7 +2378,7 @@ function resetPassword() {
     for I in $(ls /dev/sd*1 2>/dev/null | grep -v "${LOADER_DISK_PART1}"); do
       mount "${I}" "${TMP_PATH}/sdX1"
       OLDPASSWD="$(cat "${TMP_PATH}/sdX1/etc/shadow" | grep "^${USER}:" | awk -F ':' '{print $2}')"
-      [ -n "${NEWPASSWD}" -a -n "${OLDPASSWD}" ] && sed -i "s|${OLDPASSWD}|${NEWPASSWD}|g" "${TMP_PATH}/sdX1/etc/shadow"
+      [[ -n "${NEWPASSWD}" && -n "${OLDPASSWD}" ]] && sed -i "s|${OLDPASSWD}|${NEWPASSWD}|g" "${TMP_PATH}/sdX1/etc/shadow"
       sed -i "s|status=on|status=off|g" "${TMP_PATH}/sdX1/usr/syno/etc/packages/SecureSignIn/preference/${USER}/method.config" 2>/dev/null
       sync
       umount "${I}"