mountroot error 5

Hi.

Today I've upgraded one of my test machines from FreeBSD 9-STABLE to
today's CURRENT.
On a reboot I got:

Solaris: cannot find the pool label for 'zfsroot'
Mounting from zfs:zfsroot failed with error 5.

When I boot from 9.0-RELEASE DVD1 and use Live Disk, I can see that the
pool is available and healthy (version is still 28, I didn't upgrade it).
It can be imported (it's not exported when mountroot tries to mount it)
and read/written.

Can this be resolved somehow ? I recreated cachefile (when on Live CD)
and replaced with it the old one, but this didn't seem to change
anything (still same error).
I've also installed today's CURRENT (from the same obj/src tree) to an
USB stick and when booting from it (on this troubled machine) it claims
there's no zfs pools at all. I think these events may be connected.

Thanks.
Eugene.