diff --git a/target/linux/ath79/base-files/lib/upgrade/platform.sh b/target/linux/ath79/base-files/lib/upgrade/platform.sh
index a7cb455b8e9..bc19149d5c4 100644
--- a/target/linux/ath79/base-files/lib/upgrade/platform.sh
+++ b/target/linux/ath79/base-files/lib/upgrade/platform.sh
@@ -7,11 +7,28 @@ REQUIRE_IMAGE_METADATA=1
 
 routerstation_do_upgrade() {
 	local append
-	local kern_length=0x$(dd if="$1" bs=2 skip=1 count=4 2>/dev/null)
+	local sysup_file="$1"
+	local magic=$(get_magic_word "$sysup_file")
 
-	[ -f "$CONF_TAR" -a "$SAVE_CONFIG" -eq 1 ] && append="-j $CONF_TAR"
-	dd if="$1" bs=64k skip=1 2>/dev/null | \
-		mtd -r $append -Fkernel:$kern_length:0x80060000,rootfs write - kernel:rootfs
+	if [ "$magic" = "4349" ]; then
+		local kern_length=0x$(dd if="$sysup_file" bs=2 skip=1 count=4 2>/dev/null)
+
+		[ -f "$CONF_TAR" -a "$SAVE_CONFIG" -eq 1 ] && append="-j $CONF_TAR"
+		dd if="$sysup_file" bs=64k skip=1 2>/dev/null | \
+			mtd -r $append -Fkernel:$kern_length:0x80060000,rootfs write - kernel:rootfs
+
+	elif [ "$magic" = "7379" ]; then
+		local board_dir=$(tar tf $sysup_file | grep -m 1 '^sysupgrade-.*/$')
+		local kern_length=$(tar xf $sysup_file ${board_dir}kernel -O | wc -c)
+
+		[ -f "$CONF_TAR" -a "$SAVE_CONFIG" -eq 1 ] && append="-j $CONF_TAR"
+		tar xf $sysup_file ${board_dir}kernel ${board_dir}root -O | \
+			mtd -r $append -Fkernel:$kern_length:0x80060000,rootfs write - kernel:rootfs
+
+	else
+		echo "Unknown image, aborting!"
+		return 1
+	fi
 }
 
 platform_check_image() {
diff --git a/target/linux/ath79/image/generic-ubnt.mk b/target/linux/ath79/image/generic-ubnt.mk
index 4f0a6a500dd..89b9f6746da 100644
--- a/target/linux/ath79/image/generic-ubnt.mk
+++ b/target/linux/ath79/image/generic-ubnt.mk
@@ -195,7 +195,8 @@ define Device/ubnt_routerstation_common
   IMAGE_SIZE := 16128k
   IMAGES += factory.bin
   IMAGE/factory.bin := append-rootfs | pad-rootfs | mkubntimage | check-size $$$$(IMAGE_SIZE)
-  IMAGE/sysupgrade.bin := append-rootfs | pad-rootfs | combined-image | check-size $$$$(IMAGE_SIZE) | append-metadata
+  IMAGE/sysupgrade.bin := append-rootfs | pad-rootfs | combined-image | check-size $$$$(IMAGE_SIZE)
+#  IMAGE/sysupgrade.bin := append-rootfs | pad-rootfs | check-size $$$$(IMAGE_SIZE) | sysupgrade-tar rootfs=$$$$@ | append-metadata
   KERNEL := kernel-bin | append-dtb | lzma | pad-to $$(BLOCKSIZE)
   KERNEL_INITRAMFS := kernel-bin | append-dtb
 endef