May be totally out of topic 
I have several related information on this.

(1) My StarMaxen with 603ev won't have any problem for these months.

* 20020407-1.5ZC snapshot works fine.
* I have tried several 1.6_BETA1 from the beginning, but 
  works all the time.

(2)
http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=16868
is saying

| the boot loader has loaded the kernel (after the start=0x100000,
|	the kernel copyrigth line isn't even printed).

Related this, and if this symptom is saying screen stays with
---------
>> NetBSD...
>>
   start=0x100000
   (nothing more)
--------- 
my G4/400 AGP has the same situation with special case.
That is:
(1) the root partition is on wd1 NOT on wd0
(2) boot strings typed manually.

If the boot strings is set in boot-device, it works fine.
It is something like
boot-device /pci@f2000000/mac-io@17/ata-4@1f000/disk@1:10/netbsd.3
(this is not exact string, sorry).

Bill> On Tue, 11 Jun 2002, Bill Studenmund wrote:

Bill> > Can someone try Manuel's time warp, with most of the kernel at 3/14
Bill> > source, but lib/libkern/arch/powerpc at 3/13? The author of this change
Bill> > says it *should* compile.

Bill> Or, try a VERY -current kernel. Make sure you have version 1.17 of
Bill> sys/arch/powerpc/mpc6xx/cpu_subr.c. It adds specific cache support for the
Bill> 603ev CPU.

---
Makoto Fujiwara,