I’ve had this adapter for years:
It works for pretty much any emulator I throw at it out of the box except for RetroArch.
The adapter and controller gets recognized in RA by the remap files but I can’t get any input to work or reconfigure any buttons.
If I turn off automatic remap and just use the keyboard I can use a program called AntiMicro and use my SNES controller and adapter there and map the corresponding keyboard keys from RA to it.
Anyone else that have had a similar problem? It shows up in RA as Rev1 by the way.