Mounting FreeBSD partitions from DragonFly?

[walt]

Anyone aware of recent changes to FreeBSD-current which might
prevent the use of FBSD partitions from DragonFly.

I follow FreeBSD-current on a casual basis and I find after my
last update of FBSD that GRUB will no longer read from the FBSD
partiton, and DFly will also no longer mount the FBSD partition.
(An older installation of FreeBSD will still mount and use the
newly updated one, however, and fsck shows no corruption.)

I've scanned the FBSD-current mailing list but I don't see any
posts which might explain this problem.

I get an 'incorrect super block' when I try to mount the FBSD
partition from DragonFly.

Any ideas?