My church has given me an old IMac G5 (revc I think, has a webcam) that they otherwise would've thrown out. I downloaded the PowerPC debian iso from http://ftp.nl.debian.org/debian/dists/jessie/main/installer-powerpc/current/images/powerpc64/netboot/ and burned it to a CD. I put it in the Mac and powered it up while holding 'c'. I get to the "yaboot" screen and typed "expert", but when it boots it says "Invalid memory access at (and some random memory code I do not want to type)" and halts saying "Release keys to continue".
I tried video=ofonly but that did nothing. I other forum posts but their only suggestions had broken links.
What else can I do?