I finally got build.sh working on my FreeBSD 5 host. Here is what
happens when I try to boot the miniboot.fs with my sparc:

(25Mhz, 12MB RAM)

ok boot sd(,1,1)netbsd -s
Probing Memory Bank #: 1 2 3 4 5
Booting from: sd(0,1,1)netbsd -s
>> NetBSD/sparc Secondary Boot, Revision 1.14
>> (incubus@elemental.DashEvil, Sun Sep 26 16:41:42 EDT 2004)
Booting netbsd
Cannot load netbsd: error=27

device[sd(0,1,1)netbsd] ("halt" to halt):

The netbsd-GENERIC kernel from src/obj/releasedir/sparc/binary/kernel is
3,577,813 bytes ungziped.

I know this is an old thread, just trying to see if this clears anything
up at all. :P