This is odd, because your /proc/cpuinfo is almost identical to mine. It's a G4, gray box. I was and have been running dapper on it for over 6 months (in fact, it was pretty much my development box throughout the dapper release cycle).
I also have dapper running on my G4 PowerBook. I can't understand why you are having this kind of trouble. Could you perhaps try booting the liveCD for dapper and see if it works? No need to install, just booting it will suffice. ** Changed in: linux-source-2.6.15 (Ubuntu) Status: Unconfirmed => Needs Info -- 2.6.15-xx ppc kernel fails to boot on G4 https://launchpad.net/bugs/50813 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs