I've sideloaded MAME4droid and works really great with a Wireless Xbox controller. However I could not make the FireTV remote to select elements on the User Interface. In other words, if I don't have the Xbox controller, I can't play, because I can't select anything. I even tried a keyboard and mouse, and a Playstation joystick + USB adapter, and had the same luck with those. The UI_SELECT mapping would go to the Game Controller only button. I tried to modify the configuration files manually, but no luck either. What bugs me is that I don't always have the Xbox controller. I have 2 PS controllers, and a keyboard.
Did anyone experience this?? Any workaround?