The other interesting thing is that kPartitionAUXIsBootValid is not set on your OS 10.4 upgrade disk. If you try and boot from this directly from a reset, can Apple's Open Firmware actually boot it? Or does it have to be launched from OS X?
I booted it by setting boot device in OS X and using open firmware (boot cd://:tbxi), in both cases it worked fine. Is this what it means booting from reset?
Amadeusz