It's no secret that we're transitioning from the 386bSD MBR-id of 165
to our very own ID of 169.

Getting a short, but adequately informative message about the old
partition is hard.  the 

	  printf("WARNING: old BSD partition ID!\n");

is not working well. One suggestion is:

"WARNING: MBR ID 165 is obsolete. Please update to 169. See installboot(8)."


Which I think is fine except for one detail.  If we do this on a
two-disk system with NetBSD on one disk (with either ID) and with
FreeBSD on a second disk, the NetBSD kernel will warn about changing
the _FreeBSD_ dissk' ID to 169.

Since this is more-or-less the only way to have FreeBSD and NetBSD
coexist without tracking -current, that seems like a potential
problem-- especially since the message doesnt have the device name.

So I prefer something like

WARNING: MBR ID 165 for NetBSD is obsolete. See installboot(8) for upgrading.

which assumes that installboot(8) says something coherent about 

  a) updating NetBSD MBR-partition bootblocks, and then
  b) changing NetBSD MBR IDs (and those only) to 169, and
  c) the loss of backwards compatiblity with 1.3.2 and earlier kernels.


Also, I just realized that switching to 169 means that, in this
two-disks, one-for-each setup, FreeBSD wont be able to read NetBSD
disks anymore.  Will that cause problems for anyone?