'Magic numbers do not match — Improper UFS partition. Could not open kernel ”netbsd”’
Hmmmm... Does sysinst default to FFSv2 these days? What if you newfs the filesystem from the install kernel, obviously without -O 2, then copy netbsd onto it, then see if Booter sees it?
Sometime, Booter will have to be updated to support booting from FFSv2... John