autoconf —
diagnostics from the autoconfiguration code
When NetBSD bootstraps it probes the innards of the
  machine on which it is running and locates controllers, drives, and other
  devices, printing out what it finds on the console. This procedure is driven
  by a system configuration table which is processed by
  config(1) and compiled into
  each kernel.
Normally, the system uses the disk from which it was loaded as the
    root filesystem. If that is not possible, or if such a system is booted with
    the RB_ASKNAME option (see
    reboot(2)), then the name
    of the root device is read from the console terminal at boot time, and any
    available device may be used.
  - unknown CPU type
- You tried to boot NetBSD on a CPU type which it
      doesn't (or at least this compiled version of
      NetBSD doesn't) understand.
- %s%d at mainbus0
- %s%d: %s
- An on-board device controller was found.