Undo MBR

[Paul Murphy]

On Thu, 4 Sep 2003 17:38:04 -0400
Paul Murphy <pnmurphy at cogeco.ca> wrote:

> On Thu, 4 Sep 2003 13:11:25 +0100
> Matthew Seaman <m.seaman at infracaninophile.co.uk> wrote:
> 
> > On Wed, Sep 03, 2003 at 06:00:30PM -0500, David Kelly wrote:
> > > On Wednesday 03 September 2003 05:13 pm, Paul Murphy wrote:
> > > >  I have just installed FBSD-CURRENT on a test box. During
> > > >  install I
> > > > unwittingly installed a BootMgr entry for the second HDD (it
> > > > will just be a data disk, no need to boot from it).
> > > >
> > > >  If I do 'dd if=/dev/zero of=/dev/rad2 count=15' will this
> > > >  "erase"
> > > > the BootMgr or will I have to redo Fdisk and etcetera. There is
> > > > no data on the disk yet so this would be no hardship, but is
> > > > there a"proper" way of doing what I want?
> > > >
> > > >
> > > >  Just to clarify, upon booting I get:
> > > >
> > > > 	F1 FreeBSD
> > > > 	F5 Drive 1
> > > >
> > > >  but I just want to boot straight into FreeBSD, no "dual-boot".
> > > 
> > > I don't know why you are fretting about this prompt and
> > > momentarily pause in the boot process. Also think you are confused
> > > about the MBR thing on the 2nd drive.
> > > 
> > > The prompt above is coming from your first HD. If the BIOS did not
> > > know about the 2nd drive the F5 entry would not be there and the
> > > FreeBSD F1 entry would still be there. You could hide this prompt
> > > by retuning the MBR to pause 0 or 1 seconds. Zero might be
> > > infinite.
> > > 
> > > To eliminate the prompt, wipe the HD and reinstall "dangerously 
> > > dedicated." The result will be a disk which lacks the headers
> > > which allows other x86 OS's to understand what/how the disk is
> > > used.
> > 
> > Errr... That's a little excessive.  The quick way to remove the
> > FreeBSd boot manager and restore a standard MBR is:
> > 
> >     # boot0cfg -B -b /boot/mbr ad0
> > 
> > (The OP might want to do that on his data disk ad2 as well).  No
> > changes to the filesystems on those disks should be necessary.
> > 
> 
>  THAT'S what I was looking for! I knew it should have something to do
> with boot0cfg, just didn't read the man page closely enough I guess.
> 

 Hmm, problems...

# boot0cfg -B -b /boot/mbr ad0
# boot0cfg: /boot/mbr: unknown or incompatible boot code

 Now, a little bit of history:

 This is a new install if FBSD-CURRENT from binaries, after which I
realized I shouldn't have installed BootMgr. Then I tried to 'undo' it
but having no success I did the email thing.

 _Meanwhile_ I did a CVS upgrade to FBSD-HEAD (for unrelated problems).

 I shouldn't think this would cause the boot0cfg error though. The
/boot/mbr file is pretty stable code isn't it?


-- 
Cogeco ergo sum
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