Custom kernel bootloader crash on MTX604

Tracking -current, GENERIC kernels and userland seem to work very well
on the Motorola MTX604-010A.  Still have problems with losing interrupts
on the "slide" IDE controller under heavy disk I/O.

So, I wanted to try a custom kernel that removed stuff I didn't have
and added things I wanted to use.

I configured and built it, then used the nbpowerpc-mkbootimage to build
a net-boot kernel image.

The net-boot image built from my custom kernel crashes in the bootloader
before displaying anything.  Usually with ILLEGAL INSTRUCTION reported by
PPC1-Bug.  I'll try to get a register dump when I try it again.

So, to punt, I simply tweaked a GENERIC kernel to enable USB host adapters,
uhub, umodem/ucom and add cdce USB ethernet.  Then I rebuilt the system
from top to bottom (well, a -u update build).

The tweaked GENERIC installation/floppy/generic_com0.fs bootimage that
resulted crashed the same way as my custom kernel bootimage.

I'm trying to build a pristine GENERIC again, but -current has broken
the build again lately, looking for the nonexistant 'mkstemp'.

I'll try to provide more data when I can gather it, but I wanted to
record this here before I forgot about it.

Has anyone else had problems with customized kernels for PReP?

-- 
John D. Baker, KN5UKS                    NetBSD     Darwin/MacOS X
jdbaker[snail]mylinuxisp[flyspeck]com         OpenBSD            FreeBSD
BSD -- It just sits there and _works_!
GPG fingerprint:  D703 4A7E 479F 63F8 D3F4  BD99 9572 8F23 E4AD 1645