Not sure if there is a way to do this, but I have 3 different USB controllers and when I use one of my gamepads with FBA, I want to swap the L and R buttons and only with that controller. My other controller is an arcade stick and its mapping of L and R are where I want them to be. Is there a way in the retroarch.cfg for the fba emulator to change the input mapping per controller and not just per player #?

EDIT: I figured it out thanks to a reddit post. I had to copy the controller configuration into the emulator folder then point the retroarch.cfg to it.

pi@retropie:/opt/retropie/configs/fba/retroarch-joypads$ ls
LogitechLogitechDualAction.cfg MY-POWERCO.,LTD.USBJoystick.cfg

in retroarch.cfg for fba:
joypad_autoconfig_dir = /opt/retropie/configs/fba/retroarch-joypads

Now my Logitech controller is specific for FBA.

I did though have to copy all my joystick configs to this folder since it overwrites the main config dir in the main script and couldn’t find my other joysticks now for FBA.