zfs: affected by geom_(mbr|bsd) => geom_part_(mbr|bsd) ?

[Andriy Gapon]

Using GENERIC amd64 7-BETA2 system (installed from "official" ISO) I
partitioned my disk for ZFS root file system more or less as described here:
https://ish.com.au/solutions/articles/freebsdzfs

Big difference is that I created a separate slice to contain a partition
for ZFS pool, so that ZFS pool is ad4s2d (and UFS2 boot is ad4s1a).

Everything was fine, ZFS root was mounted as expected.

Then I built a custom kernel with nooptions for GEOM_(BSD|MBR) and
options for GEOM_PART_(BSD|MBR). When I tried to boot this kernel it
couldn't mount ZFS root and I simply rebooted my machine when I stuck at
mountroot prompt (I couldn't enter UFS2 root because of unrelated
keyboard problem).
The boot was verbose and I didn't see any peculiar GEOM or GEOM_PART
messages (errors, warnings).

I'll try to debug this further by booting into UFS root and running
gpart, but I'd like to ask for an advice upfront.

Can something like this be rationally expected?
Is there a way to make ZFS see its pool again (when booted into UFS root)?

Thank you!

-- 
Andriy Gapon