That might be why the Ethenret only works on some devices:
So if we try to find the documentation for that (by looking at the commits, at the official AOSP documentation, by looking on the web) add that to the devices that miss it it will probably make Ethernet work out of the box.
Note that last time I tested it in this way:
- First I plugged the USB Ethernet adapter and the Ethernet cable and made everything ready
- Then I rebooted the device
And it would then automatically get an IP address at the next boot and an (ethernet? network?) icon would appear in the top bar.