diff --git a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
index 166bc052c5..7d0ab97356 100644
--- a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
+++ b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
@@ -75,10 +75,21 @@ zyxel_do_upgrade() {
 	[ -b "${rootfs}" ] || return 1
 	case "$board" in
 	nbg6817)
-		kernel=mmcblk0p4
+		case "$rootfs" in
+			"/dev/mmcblk0p5")
+				kernel=mmcblk0p4
+			;;
+			"/dev/mmcblk0p8")
+				kernel=mmcblk0p7
+			;;
+			*)
+				return 1
+			;;
+		esac
 		;;
 	*)
 		return 1
+		;;
 	esac
 
 	zyxel_do_flash $tar_file $board $kernel $rootfs