Daniel> 1: Apple_partition_map Apple                 63 @ 1
Daniel> 2:           Apple_HFS Apple_HFS_Boot    112640 @ 64       ( 55.0M)
Daniel> 3:          Apple_Boot eXternal booter    17408 @ 112704   (  8.5M)
Daniel> 4:           Apple_UFS NetBSD_root      1031168 @ 130112   (503.5M)
Daniel> 5:     Apple_UNIX_SVR2 NetBSD_swap      4194304 @ 1161280  (  2.0G) S1  SFS k0  (swap)
Daniel> 6:          Apple_Boot eXternal booter    17408 @ 5355584  (  8.5M)
Daniel> 7:           Apple_UFS NetBSD_usr      72767168 @ 5372992  ( 34.7G)

(1) Try to get ofwboot.xcf run first, ignore netbsd / root stuff
    
(2) Try not using the partition # first

   boot hd:,ofwboot.xcf

(3) If (2) doesn't make it, try all numbers,

   boot hd:2,ofwboot.xcf 
   boot hd:3,ofwboot.xcf 
   boot hd:6,ofwboot.xcf 

   ( or all numbers 1 thru 7, I am afraid)

(4) If you get ofwboot.xcf to run, then you try netbsd / root stuff
   (using the way you got above)

  boot hd:,ofwboot.xcf hd:4/netbsd
 
I hope your good luck,
---
Makoto Fujiwara, 
Chiba, Japan, Narita Airport and Disneyland prefecture.