More Trouble installing 1.4.1...

[Paul Andrews <paul.andrews%smartmove.co.nz@localhost>]

What can be done when NetBSD gets a really bad error on
startup and drops you into the shell? It seems to mount
everything read only so I cannot fix anything. It
happened when I tried to add my ADos workbench partition
to fstab so I could copy some files - now netBSD just
has a fit when it boots and prompts me for a shell. If
I mount the usr partition (mount /usr) and try to run
vi it fails because it can't create it's temp file. And
I can't write to fstab because / is read only :-(
All I added to fstab was something like:
/dev/sd1a /wb ados rw 1 4
I can't *exactly* remember but I copied the format of
/ and /usr and incremented the last number (mount order),
so I figured it would work [the above may be in the wrong
order, but I'm at work so I can't check exactly what I did].

What can I do?