I'm having no luck with mame2003_mini. I believe I followed all the instructions.
I copied the mame2003_mini over to user_mods, along with bios_neogeo.hmod, which includes neogeo.zip in the system directory. I installed both and updated command line to mame2003. I can't get any Neo Geo games to run. I used MAME versions of the games, downloaded from different sites.
The readme file for the mini core mentions "patch-neogeo-bios" and there is a file called patch_neogeo.diff in the core_modules_extra\src\mame2003 directory. Do I need to do something with that file?