I assume you'd have to locate a 32-bit clean rom image from one of the emulator sites, then break out every 1/4 byte into a file. You then have to use an external prom programmer to write them. According to the eBay ad:
"Chips are socketed for individual flashing on a standard eprom programmer with PLCC32 adapter." On 4/26/16 3:44 PM, David Griffith wrote: > > I have a "MACSIMM" from GGLabs (http://gglabs.us) which I bought from their > Ebay store. Unfortunately they haven't > followed up on my request for information on how to prepare a ROM image for > use with the thing. Has anyone else here > used this or a similar device to hack the ROMs of the Mac SE/30, IIsi, IIci, > or IIfx? It's composed of four 39SF010A > 32-pin PLCC chips the special 64-pin SIMM. > >
