Rescuing a GPT ZFS boot setup

Andy Moran amoran at
Thu Sep 19 15:12:44 UTC 2013

On Sep 19, 2013, at 6:58 AM, Volodymyr Kostyrko <c.kworr at> wrote:

> 19.09.2013 16:43, Andrew Moran wrote:
>> 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.
> Good catch. The fix landed in stable not so long ago ( so you wouldn't find it in 9.2 either. Can you try this:
> 	gpart unset -a active ada0

It says 'active' is an invalid attribute.  This matches what gpart mangpage says under ATTRIBUTES .. it doesn't list 'active' as an attribute for the GPT partition scheme (but it does for other schemes).    I did try to unset 'bootme' but that did not help either.  

Do I need the newer version of gpart to be able to unset or set it?


More information about the freebsd-stable mailing list