I tried the firmware flashing on my dual 1.25Ghz MDD FW800 (currently has 4.6.??), and apparently it loads correctly, but after I push go, I get the following text for a fraction of a second, followed by the OS X grey prohibitory sign. I even tried the holding down the power button until a long tone comes out and then entered open firmware:
loading XCOFF
tsize=23000 dsize=2000 bsize=9c000 entry=1c12100
SECTIONS:
.text 01c00000 01c00000 00023000 000000d4
.data 01c23000 01c23000 00002000 000230d4
.bss 01c25000 01c25000 0009c000 00000000
loading .text, done..
loading .data, done..
clearing .bss, done..
_
Even with the special macos9lives cd for non-supported G4s, I see the grey screen, get a cursor, followed by the OS9 grey floppy with a flashing question mark and the cd drive comes out.
I even reformatted the primary hardddrive with a 10.2.7 cd that allowed me to install OS 9 drivers, partitioned it to be 64GB and 160GB, and copied the system folder from the cd to the 64GB harddrive, and even blessed it using the command line in OS X, but then I got the same result from the cd. (I even copied the OS9 install from the os9general.dmg from the 10.2.7 cd and replaced the ROM with the one from the macos9lives cd), but same flashing floppy result.
I don't know if it's related, but I am unable to boot into Firewire Disk Mode on that machine. I've tried unplugging the second (slave) harddrive, moved the jumper on the main (master) from master to cable select and back, disconnected the DVD drive, disconnected all harddrives, but no matter what, the computer just shuts down after a few moments. Even with the keyboard plugged directly into the USB ports (not over a hub). I've tried pram resets, taking out the battery on the motherboard.