Seen on eBay, two beta ROMs for old Macs. The first, code-named Rafiki, for a Mac IIsi, and the second for a Power Mac 8500, with the associated processor.
The Rafiki ROM obviously works in a Mac IIsi but also in an SE/30, apparently.
Rafiki
Rafiki
The second ROM comes with a 604e processor and uses Intel flash memory, making it easily modifiable.
Prototype
ROM and CPU
Beirut fix
