How to restore FreeBSD boot manager on GPT disk ?

Ian Smith smithi at
Tue Nov 8 12:52:50 UTC 2016

In freebsd-questions Digest, Vol 649, Issue 3, Message: 3
On Tue, 8 Nov 2016 10:49:23 +0000 Manish Jain <bourne.identity at> wrote:

 > One thing I have loved about FreeBSD over the years is the superbly 
 > designed Boot Easy boot manager. If any other OS overwrites the MBR, it 
 > is straightforward to restore with 'boot0cfg -B /dev/ada0'
 > That command only works on MBR disks though, as far as I know. Is there 
 > any equivalent command on a GPT disk ?

Sadly, no.  Noone has written a GPT equivalent of boot0cfg; perhaps it's 
too hard, or developers perceive no use for multi-booting; I don't know.

Often people will suggest using the GPL'd GRUB; I suppose that works ok 
with GPT disks these days.  You could research rather more complicated 
Boot Environments, about which I know nothing, but I don't think these 
enable a choice between e.g. BSD/s|Linux/s|Window/s systems as boot0cfg 
does.  [ Corrections to any misperceptions are welcome! ]

Jack L. offered:
  gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 ada0

which restores the PMBR and GPT bootblocks to ada0p1, but that's not 
(yet?) able to provide or restore multi-boot options as such.

Are you forced to use GPT, because of UEFI-only motherboards?

cheers, Ian

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