I’ve got some Neo Geo (arcade, or MVS) ROMs that I have put into the arcades folder to be used by the libretro-mame2003_plus core. I believe some configuration is needed to add the neogeo bios to the setup, but I have no clue if 1. this is the bios to get: The official UNIVERSE BIOS homepage , and 2. where to put the bios file and what config changes to make provided I have the correct bios file.
Any help appreciated.