OK, I'm running load-base 600000 and real-base F00000, booting from the 
internal CD-ROM. I burned a pure ISO-9660 with EZ CD trasher, since the 
hybrid ISO from netbsd.org doesn't work with pre OFW 3.x machines.

my boot command is boot scsi/sd@3:0,OFWBOOT.XCF;1 

OFWBOOT loads and runs, finds the kernel, starts loading and either 
freezes at the spinning pinwheel after printing the first magic number, or 
it successfully loads the kernel, the screen clears, prints the NetBSD 
copyright lines and then freezes. Same behaviour on a serial console as 
well as local display. Am I missing something here?

Booting from floppy yeilds READ TIMEOUT@READ TIMEOUT@_READ TIMEOUT@\ and 
prevents the load from completing. I'll keep trying disks, but I've gone 
through about 10 so far with varying results. OpenFirmware seems to be 
very particular about what it wants to boot. I never saw this with my 
Beige G3.

Net booting this machine is not an option as it has no onboard NIC and I 
do not have a card with a MacOS boot ROM or a flash chip capable of being 
converted to MacOS.