One thing that you usually discover when searching for info about these programmable ROM modules is that they’re compatible with the earliest 68030-based desktop Macs: the SE/30, IIx, IIcx, IIci, IIfx, and IIsi. The most common use of them is to set up a special custom bootable ROM disk using Rob Braun’s driver, Big Mess o’ Wires’ driver based on Rob’s, or Garrett’s Workshop’s driver. In general, the compatible ROM images out there are all using the IIsi ROM which is capable of booting any of the aforementioned Macs.
What you may not know is that most of the later 68k Macs also have provisions for a ROM SIMM socket, but aside from the very first Quadras (700/900/950) which always have the socket installed, it’s not usually populated. Some early production or prototype units have it, but most just have empty through-holes filled with solder where the socket would go.
Check out Doug’s thorough analysis of the ROMs and how the need to be made for later Macs in the post here.
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