Rescuing a GPT ZFS boot setup

Andrew Moran amoran at
Thu Sep 19 13:43:42 UTC 2013

Alas, that did not work.     But it does look to be BIOS related.    

I think this new system has a UEFI bios.   

I just read from
	* Partitions not seen. When using GPT, FreeBSD will create a protective MBR. This MBR has one partition entry covering the whole disk. FreeBSD marks this partition active. This causes at least some UEFI implementations to ignore the GPT. To fix this the partition needs to be marked inactive.
	* Filesystem not seen. FreeBSD's FAT32 code appears to sometimes create filesystems that the UEFI code can't properly read. If the filesystem is small enough, use FAT16 or FAT12 instead.

I think this may be my issue.  But 9.1 LiveCD does boot and I can see the data once booted, so there must be a way to fix the boot loader on the drive to work.

  Is there a way for me to reinstall the MBR or boot partition on the drives to make it boot up with this BIOS?  :(



 From: Volodymyr Kostyrko <c.kworr at>
To: Andrew Moran <amoran at> 
Cc: "freebsd-stable at" <freebsd-stable at> 
Sent: Thursday, September 19, 2013 12:51 AM
Subject: Re: Rescuing a GPT ZFS boot setup

19.09.2013 09:36, Andrew Moran wrote:
> 3 years ago I followed  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?

Maybe the machine is just too picky about partitioning scheme? Try this 
black magic:

printf '\ny\n\n\n\ny\n\ny\n\n\n\n\ny\n' | fdisk -u ${YourDiskName}

Sphinx of black quartz, judge my vow.

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