Serious ZFS Bootcode Problem (GPT NON-UEFI)

Karl Denninger karl at
Sat Feb 9 22:31:37 UTC 2019

FreeBSD 12.0-STABLE r343809

After upgrading to this (without material incident) zfs was telling me
that the pools could be upgraded (this machine was running 11.1, then 11.2.)

I did so, /and put the new bootcode on with gpart bootcode -b /boot/pmbr
-p /boot/gptzfsboot -i .... da... /on both of the candidate (mirrored
ZFS boot disk) devices, in the correct partition.

Then I rebooted to test and..... /could not find the zsboot pool
containing the kernel./

I booted the rescue image off my SD and checked -- the copy of
gptzfsboot that I put on the boot partition is exactly identical to the
one on the rescue image SD.

Then, to be /absolutely sure /I wasn't going insane I grabbed the
mini-memstick img for 12-RELEASE and tried THAT copy of gptzfsboot.

/Nope; that won't boot either!/

Fortunately I had a spare drive slot so I stuck in a piece of spinning
rust, gpart'ed THAT with an old-style UFS boot filesystem, wrote
bootcode on that, mounted the ZFS "zsboot" filesystem and copied it
over.  That boots fine (of course) and mounts the root pool, and off it

I'm going to blow away the entire /usr/obj tree and rebuild the kernel
to see if that gets me anything that's more-sane, but right now this
looks pretty bad.

BTW just to be absolutely sure I blew away the entire /usr/obj directory
and rebuilt -- same size and checksum on the binary that I have
installed, so.....

Not sure what's going on here -- did something get moved?

Karl Denninger
karl at <mailto:karl at>
/The Market Ticker/
/[S/MIME encrypted email preferred]/
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