The Yellow Dog Linux team has announced that Yellow Dog Linux will now work on PowerMac G4s. Yellow Dog Linux is a distribution of Linux for Macs. According to the Yellow Dog Linux team:
Great news! Yellow Dog Linux now installs on the latest Apple Macintosh G4s ("Sawtooth"). We owe a great deal of thanks to Benjamin Herrenschmidt of the PowerPC Linux development community for his ongoing work with Bootx, the G4 kernel, and "yaboot", a new boot loader.
With a "boot loader" it is possible to run Linux on a G4 with no Mac OS. However, you will need to maintain a small HFS partition (the drive format Mac OS requires) on which the boot loader resides. For most of us, however, the update to the BootX Control Panel for the Mac OS offers G4 support and is simpler to install.
While Troy Benjegerdes and Stephen Edie of Terra Soft Solutions have confirmed the install and functionality of Yellow Dog Linux on G4s, please understand these updates do not represent a final, fully tested product. We expect to be able to offer an officially supported download by MacWorld 2000.
The Yellow Dog Linux "Solutions Page" offers instructions for upgrading the BootX Control Panel, the YDL kernel (vmlinux), and the "ramdisk image", and (if you like to play) the introduction of the boot loader "yaboot."