Compiling for a device supported in Master but not in Stable 19.07.03

[Byte]

Hi. I have a Xiaomi Mi Router 4A which had support in the master branch starting from last year. I've successfully compiled from source and flashed a build from master. While it works, performance on 2.4 is wonky hence I want to build using stable and the Linux Version it comes with (4.14). I've added lines in images > mt7621.mk for my device and yet it does not show as a target in menuconfig. I've seen posts here in the forum that someone was able to build a firmware for the device using OpenWrt 19.07.3 r11063-85e04e9f46. While I could use that image, I'd prefer to compile things by myself (and learn in the process). Can anyone point me to the right direction?

[mpratt14]

Sorry to break this to you...but if you're having issues with wifi performance on master, having a build from stable branch is not likely to improve anything...

If wifi is really that bad for you, file a bug report:

Issues · openwrt/openwrt

I had to do a similar thing for WDR3500, which is merged into master for the new target ath79, but that commit was merged after version 19 was released, therefore they do not backport it into version 19 releases.

You can see my post and my solution here for WDR3500:

Ath79: No public image for WDR3500?

Hi all, Unfortunately I didn't notice this during the Release Candidate period of the 19.07 branch. It seems like the public image, DTS, and all other related edits for the WDR3500 is simply missing from the release, despite the commit for porting it to ath79 target being made into the master branch many months ago... For quick reference, the WDR3600 is already in the branch for ath79, and they have exactly the same hardware and board design with the exception of Gigabit ethernet. Also, I hav…

I actually forgot to mention the last step which is kind of a hack. After doing those steps, it still doesn't show up in make menuconfig so one has to edit .config manually...

I'm assuming that you're building from linux and that this is the commit for your router:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=522d5ff42835f7ad01c090b9ea1863f5d56b91d3

# clone from master if you haven't already
git clone https://github.com/openwrt/openwrt.git

# step into the build tree
cd openwrt

# switch to a new branch for this
git checkout -b 4a-stable

# force that branch to roll back to the stable release
# BTW this is a tag, you can see all tags with "git tag"
git reset --hard v19.07.3

# merge that specific commit
git cherry-pick 522d5ff42835f7ad01c090b9ea1863f5d56b91d3

# see the files that have conflicts
git status

Now there will be a merge conflict...
use git status to see the files that didn't merge (in red)

you have to correct the conflict manually in your favorite editor...

For the script 02_network:
at line 690 (or search for "mir3g-v2")

copy everything between
=======
and
>>>>>>>
and put it before

        zyxel,keenetic-start)
                wan_mac=$(mtd_get_mac_binary factory 40)
                ;;
        *)

Then you delete all 3 of the conflict markers
the other one you have to scroll up to see
<<<<<<< HEAD

If you're in doubt just make it look like the commit:

	xiaomi,mir3g)
		lan_mac=$(mtd_get_mac_binary factory 0xe006)
		;;
	xiaomi,mir3g-v2)
		wan_mac=$(mtd_get_mac_binary factory 0xe006)
		label_mac=$wan_mac
		;;
	xiaomi,mir3p)
		lan_mac=$(mtd_get_mac_binary factory 0xe006)
		label_mac=$lan_mac
		;;

For the mt7621.mk:
you can just delete the following

<<<<<<< HEAD
define Device/mqmaker_witi-256m
  DTS := WITI-256M
  IMAGE_SIZE := $(ralink_default_fw_size_16M)
  DEVICE_TITLE := MQmaker WiTi (256MB RAM)
=======

define Device/xiaomi_mir3p
  MTK_SOC := mt7621
  BLOCKSIZE := 128k
  PAGESIZE := 2048
  KERNEL_SIZE:= 4096k
  UBINIZE_OPTS := -E 5
  IMAGE_SIZE := 255488k
  DEVICE_VENDOR := Xiaomi
  DEVICE_MODEL := Mi Router 3 Pro
  IMAGES += factory.bin
  IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
  IMAGE/factory.bin := append-kernel | pad-to $$(KERNEL_SIZE) | append-ubi | check-size $$$$(IMAGE_SIZE)
>>>>>>> 522d5ff428... ramips: add support for Xiaomi Mi Wi-Fi Router 3G v2
  DEVICE_PACKAGES := \
        kmod-ata-core kmod-ata-ahci kmod-mt76x2 kmod-sdhci-mt7620 kmod-usb3 \
        kmod-usb-ledtrig-usbport wpad-basic
  SUPPORTED_DEVICES += witi
endef
TARGET_DEVICES += mqmaker_witi-256m

After correcting the conflicts:

# add all files to continue the commit
git add -A

# finish the commit
git cherry-pick --continue

# close the editor

# update package repositories and merge
scripts/feeds update -a
scripts/feeds install -a

# prepare the build system
make clean

# pick a similar target
make menuconfig
# (choose Target Mediatek MIPS, Subtarget MT7621, Profile: Xiaomi Mi Router 3G
# exit and save

if you mess it up you can git reset and git cherry-pick as much as you want
or
you can just download the dts and copy whatever other lines you need

Final step, edit .config

# edit build config manually
nano .config

search for "mir3g"
replace all instance of "mir3g" with "mir3g-v2"

this
CONFIG_TARGET_ramips_mt7621_DEVICE_xiaomi_mir3g=y

becomes
CONFIG_TARGET_ramips_mt7621_DEVICE_xiaomi_mir3g-v2=y

and
CONFIG_TARGET_PROFILE="DEVICE_xiaomi_mir3g"

becomes
CONFIG_TARGET_PROFILE="DEVICE_xiaomi_mir3g-v2"

finally....

run make

it will give a warning that configuration is "out of sync" but it continues anyway

Good luck

[Byte]

Thank you very much for this and taking time to help a total noob.
I've successfully compiled the image using your directions but the initial compile was not able to boot probably due to the naming changes (DTS file structure and the like) on master. Hence, to make my build work, I added

DTS := mt7621_xiaomi_mir3g-v2

To the /target/linux/ramips/image/mt7621.mk of the cherry picked line. I also changed

DEVICE_MODEL := Mi Router 3G

to

DEVICE_TITLE := Mi Router 3G V2

then ran

touch target/linux/*/Makefile

to make the new config appear in make menuconfig.

Again, thank you very much for this. May this also help other newbs kinda backport the stable release to their devices supported in master.