> Oops.  Am I screwed?  The system still has
> the old sunos partitions.  I can newfs these partitions and copy files
> over, but the disk doesn't seem to be bootable. :-(

I'd do something like this:
	dd miniroot onto swap
	boot single user from swap
	^C in install
	disklabel sd0 > /tmp/somefile
	Do not do a disklabel -r here, the information on disk
	is probably wrong.
	look at /tmp/somefile, edit if necessary
	disklabel -R -B sd0 /tmp/somefile
	Then continue with install

Actually a bit hard to tell will do the trick in the end.

Harald.