Each MAME version corresponds to a specific “ROM set” standard: ROMs must match the checksums (CRC, SHA1) expected by that version. An older ROM might not work with MAME 0.250 if the dump has been corrected or renamed.
But the raw set was a beast—hundreds of gigabytes of redundant data, clones, and non-working prototypes. Elias didn't want a digital landfill; he wanted a curated museum. "Time for the repack," he muttered, cracking his knuckles. mame 0250 rom set repack