>> I've seen loaders that only configure the network
>> when you run ping or tftp.  I don't recall if RedBoot is one of these
>> or not.
>
> Nope, it's not.  It comes up automatically.  Which may or may not be ideal,
> but it's how they set it up.
>
> Leaving me with the PCI mapping and interrupt fixup to figure out, and
> possibly after that problems with the sis driver, a missing PHY driver (ukphy
> seems to work), and a missing NAND flash driver.

If you're brave enough and has ability to replace NOR flash contents (these
days the main usage of pricy JTAG equipment is just a NOR writer) it'd be
a promising option to invent "your native bootloader" or to switch RB to well
regarded opensource U-boot.
It's pretty likely your initppc() routine must  have tweaks and fixups to
absorb mismatch or mistake in RB.  One of least publicized NetBSD advantage
is the existence of the LIBSA.  It's a gold mine to make intermediate bootloader
and even possible to make your own native bootloader knitting useful pieces
from src/sys/lib/libsa/ directory.  I made one for my project.  It features NFS
bootloading which is proven useful to speed up kernel development cycle.
 
Toru Nishimura/ALKYL Technology