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Date:      Wed, 03 Aug 2011 01:35:30 -0400
From:      Michael Powell <>
Subject:   Re: 8.2-RELEASE-amd64.iso weirdness (help!)
Message-ID:  <j1amge$dnq$>
References:  <20110802180606.4599d800@serene>

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Conrad J. Sabatier wrote:

> I burned a copy of FreeBSD-8.2-RELEASE-amd64-disc1.iso to CD.  It
> booted and ran OK, but I encountered some rather odd behavior in a few
> places:
> As another user mentioned elsewhere, the packages distributions are
> beyond minimal, consisting only of some basic documentation in a
> variety of locales or languages.  No software packages at all.
> Worse still, though, is what I ran across in the
> partitioning/labeling/boot record section of sysinstall; no more
> "dangerously dedicated" mode (unless you go into "expert" mode, which
> is rather a mystery to me), and worse yet, it seems that the options to
> install a plain master boot record or boot manager have no effect
> whatsoever!

"Dangerously dedicated" is being deprecated in favor of more modern ways and 
methods to slice and partition. You should no longer seek to utilize it, and 
I think, if memory serves there was some talk at one time on removing it 
from fdisk and/or sysinstall. 
> This is causing me no end of grief, as I'm trying to return this
> machine back to FreeBSD after having run Linux on it for some time.
> The only reason I initially installed Linux was that, at the time I
> bought the machine, neither my hard drive nor my CD drive were being
> recognized by FreeBSD (this has been fixed since then, I'm happy to
> report).
> The really crucial problem I'm facing right now is that I can't get
> Linux's damned "grub" off of my hard drive!   I was hoping that using
> "dangerously dedicated" mode in sysinstall would allow me to overwrite
> the lingering copy of grub on my hard drive that I just can't seem to
> get rid of.  The FreeBSD install works for the most part, despite the
> few oddities mentioned above, but when I try to boot into it afterwards,
> grub seizes control and hangs with an error code.
> I've tried numerous workarounds, using boot0cfg and both FreeBSD's and
> Linux's fdisk and friends, but to no avail.  I'm stymied at this point,
> and desperately in need of some advice here.
> Can some sage person out there help me out of this predicament?  Right
> now I feel like I'm doomed to keep running Linux or nothing at all!  I
> am dying to get back to FreeBSD again.

Sounds like you need to zero the first part of your drive. The following is 
best done before installing, rather than afterwards. Either boot a LiveFS CD 
(which I have done before) or, I believe this is also possible from the 
Fixit shell (which I have not tried). In order to gain the ability to 
"force" writes to this area do this at a root prompt:

sysctl kern.geom.debugflags=16

then to zero out the beginning of your disk do:

dd if=/dev/zero of=/dev/adx oseek=1 bs=512 count=1

where x is the drive number. This should get the grub gone. Then install as 
normal. With the grub MBR out of the way you should now be able to install 
FreeBSD bootloader/MBR as you have in the past. 


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