Ethernet Android OTG
I know the on board Nic doesn't work with Android. I will tell you however that if you use an OTG Android Nic and plug it into the USB port it works fine. I wonder if that will help with allowing the on board to work. Is it that it's not an OTG supported Nic. If so how could we change that?
This needs fixing in Android OS by Google. There is an open bug on Google for this here: https://issuetracker.google.com/issues/37096466
Please highlight this bug to Google to try and get the issue fixed.