Fixing a MBR (and more) that ??? trashed

Gayn Winters gayn.winters at bristolsystems.com
Wed Sep 14 14:05:07 PDT 2005


> -----Original Message-----
> From: Alex Zbyslaw [mailto:xfb52 at dial.pipex.com] 
> Sent: Wednesday, September 14, 2005 1:59 AM
> To: gayn.winters at bristolsystems.com
> Cc: freebsd-questions at freebsd.org
> Subject: Re: Fixing a MBR (and more) that ??? trashed
> 
> Gayn Winters wrote:
> 
> >>Alex Zbyslaw [mailto:xfb52 at dial.pipex.com] 
> >>    
> >>Why do you think it's not safe to add hard drives?
> >
> >It doesn't seem "safe" if Windows blows away the multiboot MBR that
> >FreeBSD so carefully made!  Windows overwriting the MBR 
> seems to be the reason people recommend loading Windows before loading

> FreeBSD, which I do.  I just never realized that this problem would
come back 
> to bite me when I added another disk drive.
> >  
> I know of know reason why it should.  I've added disks half a dozen 
> times without blowing away any MBRs.  Even the Windows blowing away
the 
> MBR is an annoyance, not a disaster since it is easy to rewrite.  
> Whatever pickle you find yourself in seems to have to do with 
> more than just adding a disk or Windows killing your MBR.
> 
> --Alex

I certainly am willing to admit that I'm doing something stupid!
The motherboard and its BIOS are also known to be strange.

One thing to note is that if I reconfigure (fresh FBSD install), add
hardware, and then boot first into FBSD, all is well EXCEPT the boot
loader, whose prompt is:
	F1 ???
	F2 FreeBSD
	F5 Drive 1

	Default: F2

If I select F2, then I get FreeBSD.  If I select F5 I get Windows!  I.e.
F5 gives me the same slice as does F1!!!  (Drive1 is the extra IDE
drive.)  I can't blame Windows for this, since it never got booted.
Also, if FBSD gets booted first, Windows doesn't (further) corrupt the
MBR.  Incidentally, rewriting the MBR with
	boot0cfg -B -o packet /dev/ad1
does not change anything.  The F5 option is still there, and it still
brings up the Windows that is on slice1.  If I add a third IDE drive,
the situation also remains the same.  In particular, I don't get an F9
option.

I'm still in a curious pickle, but at least this one isn't choking me!

Thanks again for the help!

-gayn





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