9.2-RELEASE kernel ignores MBR on boot disk

[Scott Bennett]

Erich Dollansky <erichsfreebsdlist at alogt.com> wrote:
> On Sun, 12 Jan 2014 06:53:29 -0600
> Scott Bennett <bennett at sdf.org> wrote:
>
> > Erich Dollansky <erichsfreebsdlist at alogt.com> wrote:
> > > On Sun, 12 Jan 2014 04:53:03 -0600
> > > Scott Bennett <bennett at sdf.org> wrote:
> > >
> > > > Erich Dollansky <erichsfreebsdlist at alogt.com> wrote:
> > > > 
> > >  >
> > > > > I only installed 9.2 once but did not face any problems with
> > > > > MBR.
> > > > >
> > > >      Did your boot drive have a MBR on it?  Or a GPT label?
> > > > 
> > > it was also MBR and not GPT. But I made a fresh install and did not
> > > do an upgrade via sources.
> > >
> >      Hmmm...  Did the stage 2 boot loader change in some important
> > way for i386 between 8.x and 9.2?  I would not have thought that
> > putting stuff into /dev would have depended upon anything in the
> > loader.  Other than the loader, what else does installkernel leave
> > unchanged? BTW, I just realized that I forgot to mention in my
> > original message that the first 9.2-RELEASE kernel I tried was built
> > with both
> > 
> I upgraded one machine from 8.x via sources to 10 around June/July 2012
> without any problems.

     Interesting.  There are some pitfalls to using GPT, largely as a
result of the placement of the backup copy of the partition map, that
I really do not want to convert the boot disk if I don't have to.
>
> > options		GEOM_PART_GPT
> > 
> > and
> > 
> > options		GEOM_PART_MBR
> > 
> > When that didn't work, I tried commenting out the first of those
> > (GPT), which was the way I had had them in my 8.2-STABLE kernel.  The
> > change made zero difference that I could see.  The messages at the
> > point of failure were the same either way.
>
> I have both on 10 and have no problems with it since I have both.

     Well, I'll hold off on 10 if possible until 10.1.  I'm on my own here
and have enough problems without reaching for the bleeding edge.
>
> It all sounds weird to me. But you can use gpart to install the loaders
> from 9.2 for a try. 
>
     However, if the 9.2 boot loaders have changed, will they still work
with my 8.2 kernel if and when I have to revert again?  This is my boot
drive we're discussing here after all.
     Anyway, thanks much for your thoughts.  Maybe one of the kernel
developers will get around to commenting.  Otherwise maybe I'll have to
try to submit a PR and wait a few months more.  I suppose in the meantime
I could try 8.4, too.  Sigh.


                                  Scott Bennett, Comm. ASMELG, CFIAG
**********************************************************************
* Internet:   bennett at sdf.org   *or*   bennett at freeshell.org   *
*--------------------------------------------------------------------*
* "A well regulated and disciplined militia, is at all times a good  *
* objection to the introduction of that bane of all free governments *
* -- a standing army."                                               *
*    -- Gov. John Hancock, New York Journal, 28 January 1790         *
**********************************************************************