About the problem when booting NetBSD under Kickstart 3.1 on
an Amiga 2000:

The 2000 is recognized as an 1200 because the 3.1 ROM (40.63) for the
2000 has the card.resource. The LoadBSD command assumes that if
it finds the card.resource that this is a 1200. It seems like
the 2000 3.1 ROM was also meant to be used on the 1200 or maybe
even the 600. So I suggest to use some other method to find
out if the machine is a 1200 or a 2000.

Blaz