mountroot prompt in the middle of updating - can't get past it

[Kurt Buff]

All,

I have a Lenovo T61 with a 100g HD that I dual boot with FreeBSD
8.0-STABLE amd64 and Windows XP.

FBSD is on ad0s2a, with ad0s2b as swap, and XP on ad0s1a.

Yesterday I booted up FBSD, started xfce4, started a terminal session,
su'ed to root and did the following - running a generic kernel:

# cd /usr/src
# make buildworld
# make buildkernel
# make installkernel

Then I exited xfce4, did sudo shutdown -r now, and got a mountroot
prompt that I now can't get past.

I can get to the loader prompt, and lsdev shows the following:

   cd devices:
   disk devices:
         disk0:     BIOS drive C:
            disk0s1: NTFS/HPFS
                disk0s2a:  FFS
                disk02sb:  swap

when I use '?' at the mountroot prompt I get:

   List of GEOM managed disk devices:
      acd0
   Loader variables:
   vfs.root.mountfrom=ufs:/dev/ad0s2a
   vfs.root.mountfrom.options=rw


I've tried entering the following at the mountroot prompt, with no success:
   ufs:/dev/ad0s2a
   ufs:/ad0s2a
   ufs:ad0s2a
   ffs:/dev/ad0s2a

and several other variations that I've found while googling, but no
success anywhere.

Does anyone have thoughts on how to remedy this?

Thanks,

Kurt