My system is FreeBSD_9.2-stable_amd64_HDD-layout=GPT
grub version=grub2-2.00_1, and grub is on its own partition (/boot/grub)
zpool version: 5000, with root on the zpool
FreeBSD's bootloader is able to boot this pool, while various grub2 attempts have failed. I think the reason is that grub2 has problems with recognizing FreeBSD's zpools. As an example of why I think this:
# grub-probe /dev/ada0p2 (partition where zpool resides)
grub-probe: error: cannot find a device for /dev/ada0p2 (is /dev mounted?).
# ls /dev/ada0*
/dev/ada0 /dev/ada0p1 /dev/ada0p2 /dev/ada0p3
Regards.