This is awesome! Using Elliots stuff here I poked through the parcels in there. It appears to contain the toolbox rom, and some drivers required to exist (and would have in the old world roms) before the toolbox can start up. the Northbridge driver being one of them.
Neat!. Excuse if I take a while to get used to this quoting business.
I think it would be very useful to dump a list of the symbols imported and exported (roughly, the system functions called) by each PEF parcel blob (driver) so we have an idea of what role it plays (and doesn't!). We should be aware that there are dozens more PEFs in the 4 MB image itself. (I might write a script to extract these.) Indeed, based on one technote and the fact that "parcels" appeared quite late in the game, I suspect that the moving of things out of the 4 MB image was a work in progress.
I actually think that the Trampoline is doing the hardware init that we're really interested in. It certainly seems to be interested in interrupts.
By the way, anyone got a G4 mini?