Need Help Editing Grub
Eric Shubert
ejs at shubes.net
Sun Jan 24 20:59:06 MST 2010
Mark Phillips wrote:
> I found a helpful post at
> http://ubuntuforums.org/showthread.php?t=159346. The best part is:
>
> 3.Type "grub" ,which makes a grumb prompt appear.
>
> 4.Type "find /boot/grub/stage1. youll get an response like "(hd0)" or in
> my case (hd0,3),use whatever your computer spitts out for the next lines.
>
> 5.Type "root (hd0,3).
>
> 6.Type "setup (hd0,3)", *other instructions says to use "(hd0) ,and
> thats fine if u want to write GRUB to the mbr. if you want to write it
> to your linux root partition, then you want the number after the
> comma,such as "(hd0,3).*
>
> In my case, /boot/grub/stage1 is at (hd1,4), so i guess I need to try
> grub
> root (hd1,4)
> setup (hd1)
> quit.
>
> Sound right?
That sounds right for you (no period after quit though).
> Mark
>
> On Sun, Jan 24, 2010 at 7:34 PM, Mark Phillips
> <mark at phillipsmarketing.biz <mailto:mark at phillipsmarketing.biz>> wrote:
>
> Eric,
>
> Maybe this is what KP was trying to say
> grub
> root (hd1,0)
> setup(hd1)
> quit
>
> Because, when I boot the system now, hd1 is my Linux drive. So I
> have to setup grub on my Linux drive while it is running. Then I
> switch the Linux drive to the first ide channel, so it becomes the
> first mbr to be read, and it has grub installed there. I believe the
> current configuration has the mbr on the first ide drive (windows)
> point to the mbr on the second ide drive (linux and grub). I have to
> break that chain so the mbr of the second ide drive is now the boot mbr.
>
> The alternative would be to switch drives now, boot with a rescue
> disk and perform
> grub
> root (hd0,0)
> setup (hd0)
> quit
>
> Does this make sense?
>
> Mark
>
>
> On Sun, Jan 24, 2010 at 7:18 PM, Eric Shubert <ejs at shubes.net
> <mailto:ejs at shubes.net>> wrote:
>
>
> Mark,
> I don't understand entirely the commands that kitepilot said to
> use either.
>
> Your menu.lst file looks correct.
>
> savedefault, along with the "default" setting listed earlier in
> menu.lst, controls which kernel is used as the default. savedefault
> means "use me to boot next time", so generally speaking, the
> computer
> boots whichever OS was running last. Providing the "default" setting
> corresponds to this behavior.
>
> makeactive and chainloader commands are used with windows
> partitions.
> makeactive makes the partition active (whatever that means, but
> windows
> seems to require it), and chainloader, which effectively passes
> control
> over to the windows loader program, not unlike what happens when the
> bios passes control to grub. At least that's what I would guess.
>
> If grub is not installed in the mbr of the 2nd drive, it needs
> to be. I
> think that might be what kp was trying to get to. In order to
> install
> grub on mbr of drive hda, issue the "grub" command at the cli.
> Then at
> the grub prompt, enter the part after the prompt:
> grub> root (hd0,0)
> grub> setup (hd0)
> grub> quit
>
> If your OS is the 2nd partition on the drive, then you'd specify:
> grub> root (hd0,1)
>
> If your drive is hdb, then you'd use hd1 in place of hd0.
>
> That drive would then run grub when it's booted.
>
> --
> -Eric 'shubes'
>
>
> Mark Phillips wrote:
> > This is what I have in menu.lst
> >
> > title Debian GNU/Linux, kernel 2.6.26-2-686
> > root (hd1,4)
> > kernel /boot/vmlinuz-2.6.26-2-686 root=/dev/hdb5 ro
> > initrd /boot/initrd.img-2.6.26-2-686
> >
> > title Microsoft Windows XP Professional
> > root (hd0,0)
> > savedefault
> > makeactive
> > chainloader +1
> >
> > So, I change
> > title Debian GNU/Linux, kernel 2.6.26-2-686
> > root (hd1,4)
> > kernel /boot/vmlinuz-2.6.26-2-686 root=/dev/hdb5 ro
> > initrd /boot/initrd.img-2.6.26-2-686
> >
> > to
> >
> > title Debian GNU/Linux, kernel 2.6.26-2-686
> > root (hd0,4) <-- change1 to 0 here
> > kernel /boot/vmlinuz-2.6.26-2-686 root=/dev/hda5 ro
> <--- change
> > b to a here
> > initrd /boot/initrd.img-2.6.26-2-686
> >
> > and remove
> > title Microsoft Windows XP Professional
> > root (hd0,0)
> >
> > What about these bad boys.....
> > savedefault
> > makeactive
> > chainloader +1
> >
> > I still don't understand the grub commands that I was told to
> use.
> >
> > Mark
> >
> > On Sun, Jan 24, 2010 at 5:58 PM, Eric Shubert <ejs at shubes.net
> <mailto:ejs at shubes.net>
> > <mailto:ejs at shubes.net <mailto:ejs at shubes.net>>> wrote:
> >
> > "every reference to hd1,0 is converted to hd0,0"
> > You need to edit this manually. hd1 in grub corresponds
> to hdb in linux,
> > and hd0 in grub is hda in linux.
> >
> > Mark Phillips wrote:
> > > I understand the flow....shouldn't I tell grub somehow
> that the
> > new boot
> > > drive is hd0,0? In your steps below, is there perhaps,
> a typo?
> > >
> > > Thanks!
> > >
> > > Mark
> > >
> > > On Sun, Jan 24, 2010 at 3:58 PM,
> kitepilot at kitepilot.com <mailto:kitepilot at kitepilot.com>
> > <mailto:kitepilot at kitepilot.com
> <mailto:kitepilot at kitepilot.com>>
> > > <mailto:kitepilot at kitepilot.com
> <mailto:kitepilot at kitepilot.com> <mailto:kitepilot at kitepilot.com
> <mailto:kitepilot at kitepilot.com>>>
> > <kitepilot at kitepilot.com <mailto:kitepilot at kitepilot.com>
> <mailto:kitepilot at kitepilot.com <mailto:kitepilot at kitepilot.com>>
> > > <mailto:kitepilot at kitepilot.com
> <mailto:kitepilot at kitepilot.com>
> > <mailto:kitepilot at kitepilot.com
> <mailto:kitepilot at kitepilot.com>>>> wrote:
> > >
> > > >> 1. How do I change grub on the Linux drive
> (hdb) to say
> > "the ...
> > > If you are running GRUB 0.XX (GRUB 1.XX is different):
> > > Boot your Debian machine and as root run:
> > > grub
> > > root (hd1,0)
> > > root (hd1)
> > > It should answer that it found the stages, verify
> that there
> > are no
> > > errors.
> > > quit
> > >
> > >
> > > Then take a backup of /boot/grub/menu.lst and and
> make sure that
> > > everything
> > > is either using UUID(s) or labels or every
> reference to hd1,0 is
> > > converted
> > > to hd0,0
> > >
> > > Verify your /etc/fstab likewise.
> > >
> > >
> > > > 2. Do I move the second drive to the first ide
> port, or
> > leave it
> > > as ...
> > > Shutdown, pull the cable from the windoze drive
> and plug it
> > to Linux
> > > drive.
> > > Turn on and pray... :)
> > > Free advice, you can't sue me ;-)
> > > YMMV
> > > ET
> > >
> > >
> > >
> > >
> > > Mark Phillips writes:
> > >
> > > > I have two ide drives in one machine - drive 1 is a
> > Windows drive
> > > and drive
> > > > 2 is a Linux drive. Using grub, I can boot into
> either
> > windows or
> > > debian. I
> > > > want to remove the windows drive and replace it
> with a larger,
> > > blank drive
> > > > for backup storage. I have a feeling if I just
> remove the
> > first
> > > drive and
> > > > put the new one there, the machine will not
> boot, since
> > the MBR
> > > is probably
> > > > on the first drive (it came with the machine,
> and I just added
> > > the second
> > > > drive for Linux). My questions:
> > > >
> > > > 1. How do I change grub on the Linux drive
> (hdb) to say "the
> > > windows drive
> > > > is dead, boot here instead, long live linux"?
> > > >
> > > > 2. Do I move the second drive to the first ide
> port, or
> > leave it
> > > as the
> > > > second ide drive and put the new drive in the
> fist ide port?
> > > >
> > > > Thanks!
> > > >
> > > > Mark
> > > ---------------------------------------------------
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>
> --
> -Eric 'shubes'
>
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--
-Eric 'shubes'
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