I've tried Linux-in-a-ramdisk on 68ks using Penguin Loader, with great success. I've been looking for a program that is similar to Penguin but uses early PPC Macs. The Macs in question, for reference, a PowerBook 5300c, and a Power Mac 7100/80.

Please don't suggest BootX, it crashes every time I attempt to load it.
Thanks!