10.1-BETA2 ZFS boot failure on sparc64

I downloaded the 10.1-BETA disc1 iso image for
sparc64, and burned it to media. I then used that
media to attempt an installation onto a spare
sparc64 machine that I have.

Using UFS as the filesystem, and more or less just
following the prompts, the system got installed OK,
and boots off of ZFS OK.

I then reinstalled onto a system that I manually
configured for ZFS.  This installation fails to boot
from the hard disk, dying like this:

---- snip, snip ----
ok reset
Res
LOM event: +487d+12h37m31s host reset
etting ... 

?
Sun Fire V120 (UltraSPARC-IIe 648MHz), No Keyboard
OpenBoot 4.0, 4096 MB memory installed, Serial #53476432.
Ethernet address 0:3:ba:2f:fc:50, Host ID: 832ffc50.

Boot device: disk0  File and args:                                    
 
>> FreeBSD/sparc64 ZFS boot block
   Boot path:   /pci_at_1f,0/pci_at_1/scsi_at_8/disk_at_0,0:a
Consoles: Open Firmware console  
Memory Address not Aligned
ok 

---- snip, snip ----

I have used my exact procedure in the past to install onto a ZFS
only sparc without issue.

Has anyone else tried booting a ZFS only sparc64 installation
recently?

-Kurt