Is there some way I could help get this working like the snes to usb adapter currently does? That adapter works automatically. If I submit autoconfig, vendor and hardware ID’s would that help?
In settings > input > p1 input binds, there should be an option to save an autoconfig profile. Once you bind your buttons, use that to save it and it will use it automatically from then on. If you submit that file to the retroarch-joypad-autoconfig repo on github, we can package it with the others.
Here is a link to the repository: https://github.com/libretro/retroarch-joypad-autoconfig/tree/master/udev
It sounds like you may have even used a Mayflash cfg that I uploaded. In any case here is that one for reference: https://github.com/libretro/retroarch-joypad-autoconfig/blob/master/udev/HuiJia%20%20USB%20GamePad.cfg
Once you generate and save the config fiile that hunterk mentioned, you can upload it to that repository and from then on that controller’s config will become part of RetroArch.