> I think it's better to just format it under netbsd, and you will get the right
> type at once, as you should treat it like a removeble media (like a floppy or
> zip).

 You forget, that NetBSD/Amiga is not able to recognize (and thus use) a
free partition unless marked as "NetBSD".

> > When I format the drive, should I use ...
> >     1. newfs /dev/sd2a
> >     2. newfs /dev/rsd2a

 This one.

Markus Illenseer