so given this disk layout:

/dev/rdisk0  map block size=512
   #:                 type name                 length   base     ( size )
   1:  Apple_partition_map Apple                    63 @ 1
   2:     Apple_Driver_ATA*Macintosh                54 @ 64
   3:     Apple_Driver_ATA*Macintosh                74 @ 118
   4:   Apple_Driver_IOKit Macintosh               512 @ 192
   5:        Apple_Patches Patch Partition         512 @ 704
   6:            Apple_HFS untitled            2097152 @ 1216     (  1.0G)
   7:            Apple_HFS untitled 2         23287094 @ 2098368  ( 11.1G)
   8:           Apple_Free                           0+@ 25385462

I should be able to use nvram to boot from the installer (located at the 
root or partition 7):

boot hd:7 ofwboot.xcf hd:7

boot.fs is in the same place, and I plan to install on /dev/rdisk1, 
 partition 6.

Xavier HUMBERT wrote:

>In message <3C3DEAE0.2010801@mac.com>,
>paul beard wrote:
>
>>stuff like this looks promising.
>>
>>EXAMPLES
>>             example% nvram boot-args="-s rd=*hd:10"
>>
>>      Set  the boot-args variable to "-s rd=*hd:10".  This would
>>      specifiy single user mode with the  root  device  in  hard
>>      drive partition 10.
>>
>
>I think this would do. The other way -selecting MacOSX for next boot
>from NetBSD seems to be harder.
>
>But, as nvram(8) is part of Darwin, maybe it's possible to
>port it to NetBSD-ppc ?
> 
>