Post #3744042
2026-07-11 12:38 UTC
@DosFox@tech.lgbt Nice, I never saw one of these!
It seems the EPROMs on the board are located at 0xf80000 in the address space and identify themselves as a test ROM (0xaa55 at offset 2), so the ROM code (starting at 0xf800a8) is called early during system startup from this piece of code in the Mac 128/512k ROM:
https://github.com/jonathanschilling/mac_rom/blob/1d1014e1f85b0e2fab42ffcffbddf3770b9fbefc/original/boot/vectors.s#L83
Replies (1)
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@DosFox@tech.lgbt 2026-07-11 14:24
@me_@sueden.social ahhh, now the interesting thing is that there's a dump of ROMs of another variant of the monsterMac that doesn't include SCSI. The ROMs are identical! This begs the question - does this ROM only fix the RAM limitation, or does it actually include a SCSI driver?