Hello, I've confirmed that the version of GRUB (2.06-2) from the 24 Mar 2022 powerpc installation CD can be used to boot other GNU/Linux operating systems on a PowerBook Pismo (Gentoo and Void both work).
I also tried many different options in the grub.cfg file in an attempt to get Mac OS and Mac OS X to boot, but I was not successful. I'll set aside the disk that I've been using for testing in case anyone wants to try to get Mac OS and Mac OS X working. I can help with testing; unfortunately, I'm neither an OF expert nor a programmer, but I would guess that the best way to make GRUB boot Mac OS and Mac OS X would be for it to do whatever yaboot does. -Stan
