Reinstalling boot blocks on a ZFS-only system

[Garrett Wollman]

In article <20130512205837.GA69605 at icarus.home.lan>, jdc at koitsu.org writes:

>You may also need to set kern.geom.debugflags=0x10 to inhibit GEOM's
>"safety measure" / to permit writing to LBA 0; see GEOM(4) and search
>for the word "foot".

If you have set up your partitioning properly (read: following the
clearly recommended best practice on the wiki), there should never,
ever be any reason to do this.  (That is why it's called a DEBUG
flag.)  The necessary and sufficient invocation is:

# gpart bootcode -b /boot/pmbr -p /boot/gptzfsloader -i 1 [a]daX

I have no idea how this works with MBR partitioning, but I would make
one suggestion in that regard: DON'T.  Whatever makes you think you
want to do that, think harder and find another way.

-GAWollman