On Thu, 20 Jul 1995, Karl Stenerud wrote:

> newfs: /dev/rsd0i: can't figure out file system partition
> /dev/sd0i on /mnt/usr: incorrect super block

I recently had the same problem when my root filesystem was toated during
SCSI driver development.  When I switched to my alternate root, I could not
newfs the primary.  I think it was also at rsd0i.  When I moved it back, or
tried some of my AmigaDOS partitions which are <i, newfs works fine.  I think
that the partition mappings for newfs were broken again when the dirty 
bits were added.

Anyway, quick and dirty solution:

move each partition you want to newfs to swap ["BSDS" or "NBS\1"], newfs 
it, then move it back.

Eduardo