That sounds really interesting, but I am confused what exactly OpenBIOS is. The Wikipedia page makes it sound like an umbrella project for all the difference versions of IEEE 1275 firmware, and then lists a bunch of different projects, including OpenBIOS as one of them:
| Project | Company |
|---|---|
| Open Firmware | Firmworks |
| SmartFirmware | CodeGen |
| OpenBOOT | Sun |
| OpenBIOS | community |
| SLOF | IBM |
did they (OpenBIOS) take up code hosting for all the company projects, are they a code merge of all the other codebases?
Speaking of which, do we know which variant Apple used, or did they write their own OpenFirmware/IEEE 1275 firmware? With G5/PPC970 chips being made by IBM, I would guess SLOF, but earlier chips were from Motorola… Hmm…
If it is just an FPGA with a RISC-V softcore, you might be able to load the Power ISA Microwatt softcore as well:
https://twitter.com/antonblanchard/status/1164289913925193729