Subject: Re: "New" NetBSD MBR boot documentation and recovery?
To: None <>
From: Thrashbarg <>
List: netbsd-users
Date: 09/08/2006 21:22:57
On Fri, 2006-09-08 at 06:14 -0500, wrote:
> Hi All,
> I've been using NetBSD since at least the 1.5xx series and still use
> the old boot loader which was common to my Mac68k and my i386
> household router/firewall/gateway boxen.
> Recently I started using vmware virtual machines to play with
> fresh releases and cvs in a way that did not threaten the "production"
> server...
> Anyway, this is note is *not* urgent because it's just
> on a test virtual machine, but someday I may update the boot loader
> on my production box. Also, soon many more of the current user base will
> be moving to the new MBR boot loader and may have these issues.
> Apologies if it's already documented somewhere...I did google the site
> and took a quick look at the NetBSD guide, which appears to still
> be written for the old boot loader. I looked for "mbr boot" and found
> nothing.
> My that I've rambled on...
> #1 If you have an unsuccessful kernel build and want to get back to
>    the previous kernel in /netbsd.old ...
>    HOW do I do it with the new MBR boot?
> #2 Is there some magic key sequence?
> #3 Also, is there some way to get the new booter to display the kernel
>    startup messages like the old booter did?
> Thanks,
> gene


To get the bootloader to boot another kernel press the spacebar when the
countdown sequence starts and type
	boot hd0a:netbsd.old
at the prompt, hd0a being the hard drive number and partition where the
kernel image is. Type help or ? at the prompt for commands too.

If you only get "NetBSD/arch ustarfs Primary Bootstrap" then you're
probably using the wrong floppy image. I use the boot-com1.fs and
boot-com2.fs disks so I get the install on my Wyse terminal which runs
off a serial port. There's information in the bootloader help to deal
with changing the default console too.

Have a look at installboot(8), it has details on installing a new
bootloader with examples including dealing with the default console.

Good Luck.