MAMEDEV Forum

The bootleg doesn't work unless you have the parent ROM, but I found that if you delete everything in nitd.zip except for 260-m1.m1, which is only 12kb, then nitdbl.zip still works. This is good because nitd.zip is 17MB while nitdbl.zip is less than 5MB. They seem identical, which is odd because NITD is supposedly 1 of only 5 games in neogeo.cpp to perform a slot check to identify bootlegs. Who bootlegged it and how did they do it?

mmmm,

That looks like to me somewhat a "non-merged" rom, instead of a "split" that you had before.

Reference: https://docs.mamedev.org/usingmame/aboutromsets.html

Bootlegs of newer Neo Geo games are a lot smaller when compressed because they use unencrypted graphics ROMs that compress better.