chrome os scrubbed my secondary GPT table :(

[Alexander Best]

hi there,

i booted the chrome os live cd (i686-0.5.307) and played a bit with it. after
rebooting freebsd (HEAD) i got this warning:

GEOM: ada0: the secondary GPT table is corrupt or invalid.
GEOM: ada0: using the primary only -- recovery suggested.

it seems chrome os used the secondary GPT table of my hdd to store some data.
how can i recover the table? the primary table doesn't seem to have been
affected by chrome os.

i read that simply `dd`'ing the primary table onto the blocks where the
secondary table is located won't work and that gpart(8) is still missing a
recovery option (which gpt(8) had).

-- 
Alexander Best