IIvx failure 3.6-current

My IIvx hangs (at loading the ramdisk?) at the end of the boot process 
using bsd.rd (12/7). dmesg appended.

I've let it sit for 2 1/4 hours... no change. I hard powercyled it & 
then did the serial console capture, appended below; it's now back up 
running 3.6-release.

OpenBSD/mac68k console
[ using 304837 bytes of bsd a.out symbol table ]
Bootstrapping OpenBSD/mac68k.
Getting mapping from MMU.
mapping: PB/IIvx (0x60?00000).  Does it never end?
                Forcing VRAM size to a conservative 1024K.
Done.
Bootstrapping the pmap system.
Pmap bootstrapped.
Moving ROMBase from 0x40800000 to 0x9a0000.
Video address 0x60b00000 -> 0xba0000.
Copyright (c) 1982, 1986, 1989, 1991, 1993
         The Regents of the University of California.  All rights 
reserved.
Copyright (c) 1995-2004 OpenBSD. All rights reserved.  
http://www.OpenBSD.org

OpenBSD 3.6-current (RAMDISK) #0: Mon Dec  6 17:18:42 EST 2004
     [email protected]:/usr/src/sys/arch/mac68k/compile/RAMDISK
Apple Macintosh IIvx, 68030 CPU+MMU, MC6882 FPU
real mem = 71303168 (69632K)
avail mem = 59846656 (58444K)
using 870 buffers containing 3563520 bytes (3480K) of memory
mrg: kernel has no ROM vectors for this machine!
adb: bus subsystem
Got following HwCfgFlags: 0xfc00, 0x    773f, 0x 10001a6, 0x40803b82
mrg: skipping egret setup
adb: calling ADBReInit
adb: using IIsi series hardware support
adb: cleanup: (length=0x2):  0xff  0x03
adb: ADBReInit complete
adb: keyboard at 2
adb: 100 dpi mouse at 3
mainbus0 (root)
obio0 at mainbus0
adb0 at obio0 (ADB event device)
intvid0 at obio0: Internal Video
intvid0: 512 x 384, 256 color
grf0 at intvid0
ite0 at grf0 (minimal console)
ncrscsi0 at obio0
scsibus0 at ncrscsi0: 8 targets
sd0 at scsibus0 targ 2 lun 0: <QUANTUM, FIREBALL540S, 1Q09> SCSI2 
0/direct fixed
sd0: 520MB, 3835 cyl, 2 head, 138 sec, 512 bytes/sec, 1065235 sec total
zsc0 at obio0
zstty0 at zsc0 channel 0: console
zstty1 at zsc0 channel 1
nubus0 at mainbus0
ae0 at nubus0: address 00:00:94:21:44:79, type MacCon Ethernet, 64KB 
memory



3.6-release dmesg:
OpenBSD 3.6 (GENERIC) #2: Mon Sep 20 16:45:22 MDT 2004
     [email protected]:/usr/src/sys/arch/mac68k/compile/GENERIC
Apple Macintosh IIvx, 68030 CPU+MMU, MC6882 FPU
real mem = 71303168 (69632K)
avail mem = 59912192 (58508K)
using 896 buffers containing 3670016 bytes (3584K) of memory
mrg: kernel has no ROM vectors for this machine!
adb: bus subsystem
Got following HwCfgFlags: 0xfc00, 0x    773f, 0x 10001a6, 0x40803b82
mrg: skipping egret setup
adb: calling ADBReInit
adb: using IIsi series hardware support
adb: cleanup: (length=0x2):  0xff  0x03
adb: ADBReInit complete
adb: keyboard at 2
adb: 100 dpi mouse at 3
mainbus0 (root)
obio0 at mainbus0
adb0 at obio0 (ADB event device)
asc0 at obio0: Apple Sound Chip
intvid0 at obio0: Internal Video
intvid0: 512 x 384, 256 color
grf0 at intvid0
ite0 at grf0 (minimal console)
ncrscsi0 at obio0
scsibus0 at ncrscsi0: 8 targets
sd0 at scsibus0 targ 2 lun 0: <QUANTUM, FIREBALL540S, 1Q09> SCSI2 
0/direct fixed
sd0: 520MB, 3835 cyl, 2 head, 138 sec, 512 bytes/sec, 1065235 sec total
zsc0 at obio0 chip type 0
zstty0 at zsc0 channel 0 (console)
zstty1 at zsc0 channel 1
nubus0 at mainbus0
ae0 at nubus0: address 00:00:94:21:44:79, type MacCon Ethernet, 64KB 
memory
root on sd0a swap on sd0b
PRAM time does not appear to have been read correctly.
PRAM: 0x83da4f80, macos_boottime: 0x41b9e4c8.