Oh! I did get it dumped right!! It looks like MAME's copy of the protection chip's embeddd ROM is bad, but if I swap to a different dump, I can get the game booting.
This confirms my dump is good, and MAME's dump is bad.

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Oh! I did get it dumped right!! It looks like MAME's copy of the protection chip's embeddd ROM is bad, but if I swap to a different dump, I can get the game booting.
This confirms my dump is good, and MAME's dump is bad.