Rescuing a GPT ZFS boot setup

[Andrew Moran]

Hey guys,

3 years ago I followed https://wiki.freebsd.org/RootOnZFS/GPTZFSBoot/Mirror  for a FreeBSD 8.1 system (which has since been upgraded to 9.1).    A couple days ago I had massive hardware failure, and wound up having to put the two drives into an entirely new PC system.

Unfortunately I'm not able to get it to boot off the hard drives.  It doesn't even show the FreeBSD bootloader menu it normally would.  The BIOS sees both drives and it can boot off the 9.1 install/Live CD without any problems.   In the LiveCD, I can see both drives partition tables ("gpart show ..") and I can import  the zpool ("zpool import zroot"), and see all my data.   I just can't seem to boot from it.   I tried rerunning the "gpart bootcode" commands on both drives (no errors), but no effect.  

It's also not beyond the realm of possibility I have some BIOS setting wrong, but the drives do show up in the POST and BIOS setting.

Does anyone know how I can make my drives bootable again?   

Thanks.

--Andy