Mac IIci ROM hack (custom startup icons)

A coworker and I were talking about how cool it would be to hack the ROM of a classic Mac. I decided to give it a shot with one of the Mac IIcis that I have laying around. I desoldered the four 32-pin DIP ROM chips and replaced them with sockets. I was able to remove the ROM chips intact, so using a Willem programmer I got an image of the ROM. I got some electrically erasable EPROMs with similar pinouts to the original ROMs (GLS27SF010 -- formerly SST27SF010) and burned a new custom ROM image. I replaced the two "blinking question mark disk" icons with black and white Apple logos and booted the IIci with no startup disk attached. Voila!

My ultimate goal was to get a custom startup chime, but the IIci has a synthesized startup chime so it's difficult to hack that (I will need to do some disassembly of the ROM). It would be cool to do this similar hack to a Mac that has a sampled startup chime, because then I could probably give it a custom startup chime. But not yet!

Category:

Science & Technology

Tags:

• apple
• mac
• macintosh
• iici
• hack
• ROM
• icon
• EPROM
• DIP
• socket
• custom
• motherboard