Hi,
I'm newly signed-up so I can share my findings. They point either to me being dim, or the need for a bit more detail in the 'Mac OS 9.2.2 Read Me ' on the disk images.
I have burned a CD from Mac OS 9.2.2 Universal Install.iso. I presume it's fine, because it boots my G4 MDD FW400, and Drive Setup autostarts as designed.
I assume this behaviour is intended to happen identically on the G4 MDD FW800, so that the install does not need a second machine? It doesn't - it won't boot from the CD, but reverts to the OSX drive. Starting with Option held down shows only the OSX drive available as a valid boot drive.
Back on my everyday Mac Mini, I mounted the MacOS9Lives.img image, dug out a FireWire external drive, and Finder copied the System Folder from the mounted MacOS9Lives onto the FW drive. On the G4 MDD FW400, I made sure the System Folder was 'blessed'. Back to the G4 MDD FW800 - starting with Option held down does not list the FireWire drive as a valid bootable volume, even though the startup sequence exercised it for a few seconds. Startup Disk does an even more thorough search on the FireWire drive, but doesn't list OS9, nor does it list the CD.
At this point, having typed the above, I scratched my head, then grabbed MacOSROM_1021_Generic.sit and substituted that ROM for the test one on the FW drive. Option-Startup on the G4 MDD FW800 now reveals the FW drive as a valid boot volume! After using OS9's Startup Disk CP, the machine meekly restarts in OS9 without needing the Option key.
Now impressed!
Cheers,