I'm trying to install Ubuntu 12.04 on my iMac G5 ALS version, and I can't get my install CD to boot. I burned a DVD-R using disk utility at the lowest speed with the Ubuntu 12.04 ISO and verified it once it was burned. I am able to select "boot from CDROM" at start by pressing c, and the disk starts reading, but it just sits there and spins and doesn't stop until I force shut down. According to the PowerPCFAQ, my iMac should be compatible with the version I am using.
It should be noted that I have tried refit but my computer is not an Intel and therefore refit won't work. The Mac is also already running yaboot since I have Debian on the Mac alongside OS X, but Debian is buggy and I can't use it.