I have a bunch of Power Mac G5s siotting around, with the cool motorola chip and I wanted to see if I could get them running something useful.
The first one I have (a powermac 7,2 with a 2.0GHz G5 chip, made in late 2006, info looked up courtesy powerbookmedic.com) will boot fine on Debian 8 (jessie), 7 (wheezy) and lubuntu 14.04 CDs no problem, but only Debian 7 sets up the yaboot partition right so it can be installed properly on the hard disk.
With Debian 8 and lubuntu it starts to boot but stops at:
Loading second stage bootstrap...
And there's a blinking file and question mark icon in the middle of the screen. I found a good post of someone with the same problem, and it was a matter of editing the yaboot.conf and then running ybin, but the options in this yaboot looked very different so I tried a different CD rather than mess with yaboot.conf.
Once wheezy was installed I upgraded to debian 8, no problem.
During one reboot it froze at some part regarding getting the radeon chip working. I found the Debian powerpc FAQ and at the yaboot prompt typed:
Linux radeon.agpmode=-1and it started up fine. I added that to the yaboot.conf but couldn't run ybin as it didn't like the partition name, so I just forgot it and it hasn't locked up since.