Two players in "Loderunner: Dig Fight"?

[larsks]

I'm running "Lode Runner: Dig Fight" (loderdfa.zip) under lr-mame2003. It opens with a side-by-side display that suggests it is meant to be played by two players side-by-side. Unfortunately, the right side game is controlled by player 3, rather than by player 2. With only two controllers attached to the Pi, what's the easiest way of making this work? The only solution I've come up with so far is to go through the input controls for the game, delete all the player 2 assignments, and re-assign those inputs to the corresponding player 3 actions.

Is there a less invasive solution (like "assign this controller to player 3")?

[mitu]

Have you tried to get into RA's input controls and select P3's controller as your 2nd controller ? Or add an override for the game (see https://retropie.org.uk/docs/RetroArch-Configuration/#custom-retroarch-override-examples) with

input_player1_joypad_index = 0
input_player3_joypad_index = 1