I have 2.6 version. Some reason only some of button works. I bought a joystick kit from eBay, it was recognized as the DragonRise Inc.Generic USB Joystick.
The Joystick and only the exit and the menu button works correctly, the rest of the 6 buttons doesn’t to anything.
I have configured RetroArch and those emulators which runs through that works just fine.
Did you do anything to modify settings? I can’t find any file I could modify.