you can find instruction in the commit description
and below
Installation
Download the OpenWrt initramfs image. Copy the image to a TFTP server
reachable at 192.168.1.70/24. Rename the image to TUF-AX6000.bin.
Connect to the serial console, interrupt the auto boot process by pressing '4' when prompted or press '1' and set
client IP, server IP and name of the image.
( We don't need to open the case or even soldering anything. We can use three goldpin wires, remove from them plastic cover from connectors and connect to the console via the case holes. We can see three console holes ( from down RX, TX, Ground - partially covered).
When pressed '1' just write image name like below:
1: Load System code to SDRAM via TFTP.
Please Input new ones /or Ctrl-C to discard
Input device IP (192.168.1.1) ==:
Input server IP (192.168.1.70) ==:
Input Linux Kernel filename (TUF-AX6000.trx) ==:
Wait for OpenWrt to boot. Transfer the sysupgrade image to the device
using scp and install using sysupgrade.
$ sysupgrade -n <path-to-sysupgrade.bin>