Root on zfs (stable9) - how to make it bootable

[uki]

Hi,

I want to install freebsd9 (stable) on zfs root, unfortunately my bios
is unable to recognize GPT discs.
I'm using MBR disc, with BSD slice (on mbr index 4) containing
freebsd-zfs filesystem.

I've no idea how to make it bootable, I've tried using:

  zpool export sys
  dd if=/boot/zfsboot of=/dev/ada0s4 count=1
  dd if=/boot/zfsboot of=/dev/ada0s4a skip=1 seek=1024
  zpool import sys


When I select F4 (slice with zfs) whilst booting the computer just turns off.
How do I make it boot? Do I need freebsd-boot slice?

I have set bootfs property on pool, and added vfs.root.mountfrom to loader.conf.


Cheers,
Łukasz Gruner