grub not showing ubuntu partition

[JD]

On 09/11/2010 07:22 AM, Tanmoy Chatterjee wrote:
> Check this link-
> http://forums.fedoraforum.org/showthread.php?t=251148
>
> On Sat, Sep 11, 2010 at 7:50 PM, Tanmoy Chatterjee <bum.jee at gmail.com 
> <mailto:bum.jee at gmail.com>> wrote:
>
>
>
>     On Thu, Sep 9, 2010 at 10:53 PM, JD <jd1008 at gmail.com
>     <mailto:jd1008 at gmail.com>> wrote:
>
>
>
>         On 09/09/2010 06:20 AM, Tanmoy Chatterjee wrote:
>         > Hello Everybody,
>         > Recently I have installed Fedora 13 in my desktop, along side
>         > previously installed Ubuntu 9.04.
>         > PROBLEM:
>         > 1) After installing Fedora, rebooting the system does not
>         come up with
>         > usual grub list of OS's and I can't log into ubuntu. I can
>         only log
>         > into fedora though I can find the ubuntu partition and even
>         browse my
>         > files there.
>         >
>         > Possible Cause:
>         > 1) At the time of fedora installation there was a step where the
>         > installation program asked to select/deselect
>         > INSTALL BOOTLOADER ON dev/sda and come up with an edit/add
>         option in
>         > boot loader operating system list.
>         > 2) As an end user I prefer the default option for the
>         installation
>         > which in this step assumes there is no other OS in the
>         system and
>         > thereby ignores my ubuntu partition on the grub list.
>         > 3) Kindly give me some step by step instruction other than
>         > reinstalling everything to boot into ubuntu.
>         >
>         > I have gone through the fedora installation guide where some
>         command
>         > line solutions have been suggested.
>         > Can anybody suggest some other solution for a novice like me?
>         >
>         > Thanks in advance for any suggestion
>
>
>         How about adding an entry in grub.conf that is similar
>         to how we boot windows from grub:
>
>         title Ubuntu-9.04
>                 rootnoverify (hd0,0)
>                 chainloader +1
>
>         I do not know which disk/partition your ubuntu is on,
>         so you have to adjust (hd0,0) accordingly.
>
>         This will work, if you installed ubuntu's bootloader on it's
>         partition.
>
>     Thank you JD for you suggestion. I have taken the following steps-
>
>     Step1:
>     I add
>     [QUOTE]title Ubuntu 9.04 kernel 2.6.28-19-generic
>     root (hd0,0)
>     kernel /vmlinuz-2.6.28-19-generic root=/dev/sda1
>     initrd /initrd.img-2.6.28-19-generic
>     ---------[/QUOTE]
>     Step2:
>     [QUOTE]title        Ubuntu 9.04, kernel 2.6.28-19-generic
>     uuid        e9918b34-80aa-4214-bd63-6b46b339005c
>     kernel        /boot/vmlinuz-2.6.28-19-generic
>     root=UUID=e9918b34-80aa-4214-bd63-6b46b339005c ro quiet splash
>     initrd        /boot/initrd.img-2.6.28-19-generic
>     quiet[/QUOTE]
>     Both time after restarting the computer and selecting ubuntu in
>     GRUB list gives me this error message
>     " Error 15: File not found
>     Press any key to continue..."
>     Step3:
>     Then I edited the grub.conf file again and add
>     [QUOTE]title    Ubuntu 9.04, (kernel 2.6.28-19-generic)
>     root  (hd0,0)
>     kernel        /boot/vmlinuz-2.6.28-19-generic
>     root=UUID=e9918b34-80aa-4214-bd63-6b46b339005c ro quiet splash
>     initrd        /boot/initrd.img-2.6.28-19-generic
>     quiet[/QUOTE]
>     And then there is no problem in logging into my ubuntu system.
>

The reason ubuntu fails to boot is because
1. When you had installed Ubuntu, you installed grub on the MBR of sda (hd0)
2. When you installed Fedora, you clobbered Ubuntu's grub.
3. When you added

title Ubuntu 9.04 kernel 2.6.28-19-generic
root (hd0,0)
kernel /vmlinuz-2.6.28-19-generic root=/dev/sda1
initrd /initrd.img-2.6.28-19-generic

you instructed grub that Ubuntu's kernel and initrd are located in the /boot
directory of the Fedora root parition.
you did not have Ubuntu's vmlinuz, nor ubuntu's initrd  in Fedora's  
/boot directory.

4a- Delete your current entries for the Ubuntu in grub.conf.

4b- You must set up the Ubuntu entry as follows:
title Ubuntu-9.04
         rootnoverify (hd0,0)
         chainloader +1

No kernel, no initrd ....etc.

5. THIS IS THE CRUICIAL STEP
     a- Boot from the Ubuntu Rescue mode
     b- Let it mount the Ubuntu Partition. I do not use ubuntu, so I am 
not sure if
         it will mount the ubuntu partition as /mnt/sysimage, as Fedora 
does.
         You need to figure this one out. Type the command
         mount
         and see where /dev/sda1 is mounted.
         Let's assume it is mounted on /mnt/ubuntu
         chroot /mnt/ubuntu
         grub-install --recheck /dev/sda1
         exit (from chroot shell)
         eject /dev/sr0
     c- reboot the system.

 From the grub boot menu, select Ububtu.

WARNING: POSSIBLE CAVEAT EMPTOR:
grub-install --recheck /dev/sda1  COULD/MIGHT/WILL clobber the start of 
the filesystem on sda1.
I simply have not done this myself. So, you need to do some more 
googling to see if it is a safe thing to do.
Normally, installation of the grub boot on the partition instead of the 
MBR should be done at the time you
install the OS.

Good luck!