Seems it is better that I can post a beta firmware here.
It has many bugs though. The 3.214 firmware of AX1800 is much stable.
Changing from 3.x to 4.0 Beta:
Download the img file and upgrade in your 3.x firmware. Do NOT keep settings. Otherwise it does not boot.
You can also use uboot mode to change to 4.x or change back to 3.x.
You do NOT need to report obvious bugs because we are on that now.