I downloaded the october 20 sparc ALPHA2 snapshot from:

ftp.netbsd.org:/pub/NetBSD/NetBSD-1.5_ALPHA2/sparc/installation/cdrom/netbsd-sparc.iso

burned it onto a CD, and booted it on a sparcstation 2; the kernel
booted ok:

Boot device: /sbus/esp@0,800000/sd@6,0:c   File and args: 
>> NetBSD/sparc Secondary Boot, Revision 1.9
>> (root@flambard, Fri Oct 20 02:01:20 MEST 2000)
Booting netbsd
2380621+115892+235192 [68+153296+111862]=0x2ebc8c
OBP version 2, revision 2.4 (plugin rev 2)
Copyright (c) 1996, 1997, 1998, 1999, 2000
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.
...

found devices, etc., and then prompted for a root partition:

with cd0{b,d,e,f,g,h} it reports:

root device (default cd0e): cd0d
dump device (default cd0b): 
file system (default generic): 
root on cd0d dumps on cd0b
no file system for cd0 (dev 0x1203)
cannot mount root, error = 79

with cd0a or cd0c, it falls over with:

root device: cd0a
dump device (default cd0b): 
file system (default generic): 
root on cd0a dumps on cd0b
root file system type: cd9660
warning: no /dev/console
init: not found
panic: no init
syncing disks... done

"oops."

						- Bill