I noticed byuu's tweet about his dump of the PAL version of Maximum Carnage not matching the one that's in all the hash lists, and had a look. Other than the header checksums, there are 3 changed bytes, very close to each other. Opening the ROM in a tile viewer, it's immediately obvious that the changed bytes are part of an uncompressed sprite. That sprite turns out to be part of Spider-Man's walk animation, which you can see immediately after starting a game.
The dump that's in all the hash lists:
byuu's redump:
See the gray pixels on Spider-Man's leg and hand in the old dump? The sprite in byuu's redump exactly matches the US version (though they're offset by a few dozen bytes--the sprite in the PAL ROM starts at $50FF9, the one in the US ROM at $51028)
Either someone had a copy of the game on old 1.44MB floppies or something that bitrotted, ran a checksum fixer on it, and this hacked-checksum version got accepted as "good" by both Cowering and No-Intro, or Nintendo of Europe actually manufactured a version of the game with a bad sprite, and later released a fixed version without bumping the version number.
If it's not too much trouble, I wonder if byuu could open up his cartridge and describe the label on the mask ROM.
The dump that's in all the hash lists:
byuu's redump:
See the gray pixels on Spider-Man's leg and hand in the old dump? The sprite in byuu's redump exactly matches the US version (though they're offset by a few dozen bytes--the sprite in the PAL ROM starts at $50FF9, the one in the US ROM at $51028)
Either someone had a copy of the game on old 1.44MB floppies or something that bitrotted, ran a checksum fixer on it, and this hacked-checksum version got accepted as "good" by both Cowering and No-Intro, or Nintendo of Europe actually manufactured a version of the game with a bad sprite, and later released a fixed version without bumping the version number.
If it's not too much trouble, I wonder if byuu could open up his cartridge and describe the label on the mask ROM.