Can FreeBSD boot from a pool comprised of multiple vdevs?

[Matt Reimer]

Is FreeBSD able to boot from a pool comprised of multiple vdevs? If
not, what would it take to get it working?

I got 8.0-BETA4 booting from a pool comprised of a single raidz vdev,
but when I added another raidz vdev it fails to boot with this error:

ZFS: i/o error - all block copies unavailable
ZFS: can't read object set for dataset lld
Can't find root filesystem - giving up
ZFS: unexpected object set type lld
ZFS: unexpected object set type lld

FreeBSD/i386 boot
Default: glamdring:/boot/kernel/kernel
boot:
ZFS: unexpected object set type lld

(Apparently loader's printf() doesn't understand %lld.)

Boots successfully with gptzfsboot:

# zpool status
  pool: glamdring
 state: ONLINE
 scrub: none requested
config:

	NAME                     STATE     READ WRITE CKSUM
	glamdring                ONLINE       0     0     0
	  raidz1                 ONLINE       0     0     0
	    label/glamdring-0.0  ONLINE       0     0     0
	    label/glamdring-0.1  ONLINE       0     0     0
	    label/glamdring-0.2  ONLINE       0     0     0

errors: No known data errors

Does not boot:

# zpool status
  pool: glamdring
 state: ONLINE
 scrub: none requested
config:

	NAME                     STATE     READ WRITE CKSUM
	glamdring                ONLINE       0     0     0
	  raidz1                 ONLINE       0     0     0
	    label/glamdring-0.0  ONLINE       0     0     0
	    label/glamdring-0.1  ONLINE       0     0     0
	    label/glamdring-0.2  ONLINE       0     0     0
	  raidz1                 ONLINE       0     0     0
	    label/glamdring-1.0  ONLINE       0     0     0
	    label/glamdring-1.1  ONLINE       0     0     0
	    label/glamdring-1.2  ONLINE       0     0     0

errors: No known data errors

Thanks in advance.

Matt