Excerpts from netbsd: 20-Mar-97 Re: new stand/netboot too big Bill
Sommerfeld@orchard. (671)

> I had trouble with installboot, at least as
> it's used by the ssto makefiles..  it appears to want to write to the
> raw device of a mounted filesystem, and when it opens up the raw
> device for writing it gets EBUSY (because the corresponding block
> device has a mounted filesystem on it).  I had to hack it to unmount
> the filesystem at the right place, which leads me to wonder how this
> ever worked for him..

Thats with securelevel >=1, right?
Call it a known problem.
Unmounting isn't always a solution, you might want to install
boot blocks on your current root device.
Iirc, disklabel uses not the mounted partition to put the bootcode
to disk but a partition which overlaps it - c (or d on PC?, have to
check). Imo, this is no real solution. It shows a weakness in the
securelevel design instead.
Perhaps installboot could:
-mount the partition if not already done
-before writing raw, unmount if it was not mounted
Then it fails if applied to a mounted disk if securelevel >=1,
but this is what securelevel is made for.

best regards
Matthias Drochner