I tried to install OWRT on Ubnt Unifi (one of the first HW).
Installation went OK, OpenWRT is running, but I'm still not able to get ethernet to work.
I had to connect through TTL, after enabling wifi I was able to connect to the device.
In SSH I got messages:
I tried 19.07 snapshot and 21.02.0-rc3. In LUCI I didn't found anything wrong.