installing Fedora 11 on dual-boot machine changes active partition?

Matthew Saltzman mjs at
Sun Aug 16 22:38:58 UTC 2009

On Sun, 2009-08-16 at 17:36 -0400, Andre Robatino wrote:
> On 08/16/2009 05:24 PM, Steven Stern wrote:
> > On 08/16/2009 04:00 PM, Andre Robatino wrote:
> >> My father has a dual-boot Vista/Fedora 11 machine, with Grub on the MBR.
> >>  He recently enabled recommended updates in Vista, and it wanted him to
> >> install SP2, but he was unable to.  At Stage 3, after rebooting, it got
> >> to 100% but then failed and reverted the changes.  The associated error
> >> number was 80004005.  We found that the source of the problem was that
> >> the active partition was the Fedora /boot partition, not the Windows
> >> one.  By using Vista's Disk Management tool to make the Vista partition
> >> active again, the problem was solved.  Grub doesn't seem to care which
> >> partition is active (at least if it's on the MBR).  Looking at old saved
> >> fdisk output from 2 of my machines, I suspect that F11 changed the
> >> active partition, and that in F10 and earlier, the Windows partition was
> >> active.  Is this new behavior in the F11 installer (to change the active
> >> partition, even though Grub doesn't care), and if so, is it deliberate?
> > 
> > 
> > I went through this and the solution is obscure but easy.  He needs to
> > change the active partition to the Windows partition.  Except for the
> > SP2 install and the ability for Vista to hibernate, neither Vista nor
> > Fedora cares about what partition is flagged as active.
> > 
> >
> Yes, if you read my message again, you'll see that we already discovered
> this (except for the Vista hibernation part - does Fedora hibernation
> care which is active?).  My question is, given that this is the case,
> why does the F11 installer change the active partition if it doesn't
> have to?
> P.S.  Prior to discovering this, everything I was able to find with a
> web search suggested that it was necessary to temporarily replace Grub
> with Vista's bootloader, then apply SP2, then put Grub back.  Maybe
> that's completely wrong and the only reason it works is that it changes
> the active partition back to Vista.

Generally, for dual boot machines, I install grub in /boot and make it
active.  That way, I haven't touched the MBR.  In case warranty service
is needed (or apparently in case of the Vista SP2 update, etc.), I can
just change the active partition and Windows boots as though there's
nothing else on the machine.  

In the past, at least, that had to be done with a rescue disk after the
Fedora install, because Fedora did not change the active partition.  In
fact, I filed a bug at one point requesting that the user have the
option to change the active partition during the install if he didn't
use the default boot record.  It was closed WONTFIX.  I'm pretty sure
the default is still to install grub in the MBR and not to change the
active partition.  

The active partition must be one with grub installed.  If you install
grub in /boot and not in MBR, then /boot must be active, and vice versa.
If you somehow get grub installed in both places, then either can be
active, but you need to be careful to coordinate switching active
partitions and updating grub. 

When I installed F11 over F10 configured with /boot active,
specifying /boot as the target for grub, it did not change the active

                Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu

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