Linux vs. NetBSD disk enumeration

[Jeff Rizzo <riz%tastylime.net@localhost>]

When I'm working with EC2 images, I can successfully get NetBSD to boot 
by attaching block devices as "/dev/sda1" and "/dev/sda2" which come up 
as xbd0 and xbd1 (respectively) consistently.  However, if I attempt to 
have the domU start with one of their "ephemeral" block devices as, say, 
"/dev/sda3" or "/dev/sdf", these devices are attached by NetBSD in a 
different order, and I get an error because the kernel can't then find 
/sbin/init (because suddenly it's not on xbd1 like it should be)

A quick glance at kernel configs doesn't give me a clue how I might wire 
these down; I assume the xenbus "id" is needed, but of course, this will 
be different every time.

Any suggestions?

Thanks,
+j