Guest poster Rairii reports a milestone in a personal project: porting classic Mac OS to Nintendo GameCube and Wii hardware. The Wii-based system booted Mac OS 7.6 and Mac OS 9.2.2 to the desktop, likely the first time someone outside Apple has done so on a new system since the CHRP clone era.
The project grew out of earlier work porting Windows NT to PowerPC Macs. That effort introduced Rairii to classic Mac OS, whose long history of hacks upon hacks they describe as charmingly "jank." The project began on 2025-06-22, when Rairii forked upstream Open BIOS, and was built entirely by hand, without any coding agent or LLM, for the sake of learning and fun.
Classic Mac OS on New World hardware starts with a bootloader called the Trampoline, which runs in an Open Firmware environment, so Open BIOS had to be ported first. Rairii drew on Goldfish64's Wii port of Open BIOS, adapted an existing display driver, and switched the NT firmware loader to load big-endian ELF files. Disk support came from two EXI-bus drivers: the SD Gecko and an EXI-IDE driver tested against a Dolphin emulator build.
Early testing used the Mac OS ROM file placed on a FAT filesystem, since the on-disk format remained undecided. Rairii also found that the Trampoline assumed a physical address layout this hardware does not have, and patched it to valid addresses at run time so that unmodified CD images could eventually be used. Rairii says the project is still far from a public release.
Source: Hacker News · Summarized by HeadlinesBriefing