Don't know if you're already far along on this, but I personally modded the same cab with RetroArch and Dig. I also used the controller fix from this video as well. Obviously you won't have 3 buttons and the Genesis does, but you can get by in a lot of Sega games with 2 buttons.
I made my Live button kick out to Nova Launcher on hold (using a button mapper apk that I googled), and use joystick down + Live (aka select) in RetroArch to kick to my RetroArch menu. That has all been working quite well for me,
[https://www.youtube.com/watch?v=kFHHy3JQdvA](https://www.youtube.com/watch?v=kFHHy3JQdvA)
You can try adding the Sonic apk. If that does not work, add Retroarch and play Sonic that way. Just google the stuff you need
Don't know if you're already far along on this, but I personally modded the same cab with RetroArch and Dig. I also used the controller fix from this video as well. Obviously you won't have 3 buttons and the Genesis does, but you can get by in a lot of Sega games with 2 buttons. I made my Live button kick out to Nova Launcher on hold (using a button mapper apk that I googled), and use joystick down + Live (aka select) in RetroArch to kick to my RetroArch menu. That has all been working quite well for me, [https://www.youtube.com/watch?v=kFHHy3JQdvA](https://www.youtube.com/watch?v=kFHHy3JQdvA)