>Because my BIOS doesn't seem to like the NetBSD disk (wd1 on an old 
>486), I need to boot via a floppy.  If I use the install floppy and 
>interrupt the boot process, I can say
>
> boot wd1a:netbsd
>
>and all is cool.  But I'd rather the machine be able to boot unassisted.
>
>I tried building a kernel with the following line:
>
> config          netbsd  root on wd1a type ffs
>
>But that kernel won't boot, even via the install floppy; the machine 
>just sits there.


I don't think you need to modify the GENERIC kernel to get
the results you seek (?).

Instead, install a boot loader on wd0 *and* wd1 that will
allow the boot sequence to be passed to the second (wd1) disk.

For example, I use BootEasy installed on wd0 and wd1.
The PC wants to book off of wd0 ("C:") and drags in the
MBR from that disk as part of the IPL.  Since BootEasy
replaces the traditional "MBR", it can then present
a menu of boot choices -- something like:
  F1 wd0 partition 1
  F2 wd0 partition 2
  F3 wd0 partition 3
  F4 wd0 partition 4
  F5 wd1
Pressing F5 gives you a similar menu:
  F1 wd1 partition 1
  F2 wd1 partition 2
  F3 wd1 partition 3
  F4 wd1 partition 4
  F5 wd0

Only valid partitions are listed.  And, instead of
"wd? partition ?" the menu item will be labeled
something like "FreeBSD", "DOS", "Mach", etc. as
determined by examining the magic numbers in the
partition ID field(s).

Anyway...  if no key is pressed within a certain
time interval, a "default" action is taken.  THE
DEFAULT IS WHATEVER YOU DID LAST TIME YOU BOOTED
THE MACHINE!

So, once the MBRs are set up and NBSD is on wd1a,
for example, press "F5" at the first prompt to select
wd1.  Then press F1 at the next prompt to select
NBSD on the "first" partition of *that* disk (wd1).

Thereafter, you should see the NBSD boot prompt, etc.

I am not sure what the "boot selector" shipped in NBSD
does but I imagine it is similar...

Apologies if I have missed some detail in your problem
description...  <:-(

>Btw -- to build the boot floppy, I'm trying the following recipe posted 
>by Patrick Welche a few months ago, save that I changed fd0a to rfd0a 
>in the newfs line:
>
> disklabel -r -w /dev/fd0a floppy3
> newfs /dev/fd0a
> /usr/mdec/installboot -v -f /usr/mdec/biosboot.sym /dev/rfd0a
> mount /dev/fd0a /mnt
> cp yourkernel /mnt
>
>That seems to have the same failure mode, which is of course not 
>surprising.
>
>Any suggestions?