Xiaomi 4A 3-Gigaport cannot flash OpenWrt 21.02

fwiw, did you see the English instructions contained in separate folder, which I created in the dropbox?
dropbox folder

The bat files and python scripts have already been translated to English, but only ones I frequently use are, and known to work are:

0.start_main.bat
1.start_create_backup.bat
5.start_write_OS.bat

ps. I've added a link to your last post to the device wiki's Debrick section regarding use of 2to3 bin file.

btw, did you keep original uboot ?