BTW this is what happens when I boot `netbsd.ofcons':

>> NetBSD/powerpc OpenFirmware Boot, Revision 1.3
>> (tsubai@ruri, Tue Jan 27 20:36:27 JST 1998)
bad partition number, using 0try MBR!
open scsi/sd@2:0,netbsd.ofcons/netbsd: Input/output error
Boot: scsi/sd@2/netbsd.ofcons
Booting scsi/sd@2/netbsd.ofcons
874944@0x100000+72988@0x1d59c0 
 start=0x100000
openfirmware = 0xff8099b8
endkernel = 0x1f0f50
Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 1.3 (POWERMAC) #2: Mon Feb 16 16:06:31 JST 1998
    tsubai@powermac:/a/1.3/src/sys/arch/powermac/compile/POWERMAC
CPU: 604ev (Revision 204)
real mem = 67108864
avail mem = 60137472
using 819 buffers containing 3354624 bytes of memory
mainbus0 (root)
ofroot0 at mainbus0
ofbus0 at ofroot0 (PowerPC,604)
l2-cache at ofbus0 not configured
memory at ofroot0 not configured
AAPL,ROM at ofroot0 not configured
ofbus1 at ofroot0 (bandit)
ofbus2 at ofbus1 (gc)
ofbus3 at ofbus2 (53c94)
sd at ofbus3 not configured
st at ofbus3 not configured
mace at ofbus2 not configured
ofbus4 at ofbus2 (escc)
ofcons0 at ofbus4 (ch-a)
ch-b at ofbus4 not configured
awacs at ofbus2 not configured
swim3 at ofbus2 not configured
ofbus5 at ofbus2 (via-cuda)
ofbus6 at ofbus5 (adb)
keyboard at ofbus6 not configured
mouse at ofbus6 not configured
pram at ofbus5 not configured
ofrtc0 at ofbus5 (rtc): rtc
power-mgt at ofbus5 not configured
ofbus7 at ofbus2 (mesh)
sd at ofbus7 not configured
st at ofbus7 not configured
nvram at ofbus2 not configured
ofbus8 at ofroot0 (chaos)
control at ofbus8 not configured
cpu0 at mainbus0: L2 cache enabled
trap type 200 at 19ee3c
Press a key to panic.