I'm really losing my marbles here.
I have wired my I-PAC Ultimate I/O to my buttons and configured it to emulate a keyboard.
When I go to EmulationStation and configure player, it shows up as a keyboard and I configure it successfully.
I am unable to configure the 2nd player controls (which is also keyboard on the I-PAC) as it just overwrites the first player.
When I try to join a game with the controller I set up last, it gets to the game and just doesn't work. I end up having to use my USB keyboard to go back to ES.
I cannot find any config file that'd let me map the buttons directly. What am I doing wrong? This is driving me slightly insane - countless hours of Googling and no results.
I also tried programming the I-PAC to simulate a controller but that wouldn't get detected by ES at all.