ramips: append tail to WF2881 initramfs image

Stock firmware has a vendor-defined tail at the end of uImage for image
validation. This patch enables OpenWrt installation from stock firmware
without having to access the UART console.

Installation via web interface:
1.  Flash **initramfs** image through the stock web interface.
2.  Boot into OpenWrt and perform sysupgrade with sysupgrade image.

Signed-off-by: Sungbo Eo <mans0n@gorani.run>
(cherry picked from commit be3e98ce26da5e737744427e1d59dd1c0508edef)

diff --git a/target/linux/ramips/image/mt7621.mk b/target/linux/ramips/image/mt7621.mk
index 9c16705e2fd1a7b05afb2feae2be0e1d5eb6fe8a..28ae0d451fb0ac4dfd6a1a3d30da49587c326553 100644 (file)
--- a/target/linux/ramips/image/mt7621.mk
+++ b/target/linux/ramips/image/mt7621.mk
@@ -60,6 +60,12 @@ define Build/wr1201-factory-header
        mv $@.new $@
 endef
 
+define Build/netis-tail
+       echo -n $(1) >> $@
+       echo -n $(UIMAGE_NAME)-yun | $(STAGING_DIR_HOST)/bin/mkhash md5 | \
+               sed 's/../\\\\x&/g' | xargs echo -ne >> $@
+endef
+
 define Build/ubnt-erx-factory-image
        if [ -e $(KDIR)/tmp/$(KERNEL_INITRAMFS_IMAGE) -a "$$(stat -c%s $@)" -lt "$(KERNEL_SIZE)" ]; then \
                echo '21001:6' > $(1).compat; \
@@ -544,6 +550,8 @@ define Device/wf-2881
   IMAGE_SIZE := 129280k
   KERNEL := $(KERNEL_DTB) | pad-offset $$(BLOCKSIZE) 64 | uImage lzma
   UBINIZE_OPTS := -E 5
+  UIMAGE_NAME := WF2881_0.0.00
+  KERNEL_INITRAMFS := $(KERNEL_DTB) | netis-tail WF2881 | uImage lzma
   IMAGE/sysupgrade.bin := append-kernel | append-ubi | append-metadata | check-size $$$$(IMAGE_SIZE)
   DEVICE_TITLE := NETIS WF-2881
   DEVICE_PACKAGES := kmod-mt76x2 kmod-usb3 kmod-usb-ledtrig-usbport wpad-basic