UFS2 or such problem

[Pete Carah <pete@xxxxxxxxxxxx>]

I made the mistake of trying to "upgrade" a FBSD 5.2 system to dragonfly
and rather badly shot myself in the foot; neither dfly nor 4.x will mount
the file system...

I remember some vague planning a couple of months ago about trying to
cope with this and wondered what can be done to recover short of reinstalling
5.2 from a CD?

4.9 as I remember had a fsck option that would undo at least some of what 
5.x did.  It looks like dfly doesn't.  Is there a mount option currently 
present to handle this or do I just have to give up and go back to 5.2?

As a side note, does anyone here know what is different with 5.2.1?  I can't
find anything on the web site about this, either in the errata or RE pages.

-- Pete