Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Grub Error 21

  1. #11
    Join Date
    Mar 2010
    Beans
    Hidden!

    Re: Grub Error 21

    Everything seems fine but for
    ============================= Boot Info Summary: ==============================

    => GAG is installed in the MBR of /dev/sda
    You will need to Re-install grub to the MBR from the live disk with /dev/sda5 being the root partition.
    From the live disk
    Code:
    sudo mount /dev/sda5 /mnt
    Then
    Code:
    sudo grub-install --root-directory=/mnt /dev/sda
    .
    Then
    Code:
    sudo umount /mnt
    And then reboot the machine, grub menu should come up now.
    Note windows 7 loader is listed in grub.cfg so re-installing grub will also give access to windows. To access an external os later on just plug it in then in 10.04 run
    Code:
    sudo update-grub
    and it should be picked up as bootable by Lucid and added to the menu. To remove from the menu unplug and use the "update-grub" command abve again.

    Edit: this is where i got most of the info http://ubuntuforums.org/showthread.php?t=1195275
    .particularly section 13.
    Last edited by yetiman64; June 4th, 2010 at 04:13 PM.

  2. #12
    Join Date
    Jun 2010
    Location
    Derby
    Beans
    72
    Distro
    Ubuntu

    Cool Re: Grub Error 21

    Quote Originally Posted by yetiman64 View Post
    Everything seems fine but for
    You will need to Re-install grub to the MBR from the live disk with /dev/sda5 being the root partition.
    From the live disk
    Code:
    sudo mount /dev/sda5 /mnt
    Then
    Code:
    sudo grub-install --root-directory=/mnt /dev/sda
    .
    Then
    Code:
    sudo umount /mnt
    And then reboot the machine, grub menu should come up now.
    Note windows 7 loader is listed in grub.cfg so re-installing grub will also give access to windows. To access an external os later on just plug it in then in 10.04 run
    Code:
    sudo update-grub
    and it should be picked up as bootable by Lucid and added to the menu. To remove from the menu unplug and use the "update-grub" command abve again.

    Edit: this is where i got most of the info http://ubuntuforums.org/showthread.php?t=1195275
    .particularly section 13.

    Yeti:

    This is what I got so far -

    ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
    ubuntu@ubuntu:~$ sudo grub-install --root-directory=/mnt /dev/sda
    Installation finished. No error reported.
    ubuntu@ubuntu:~$ sudo umount /mnt
    ubuntu@ubuntu:~$ sudo update-grub
    /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
    ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
    ubuntu@ubuntu:~$ sudo update-grub
    /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).

  3. #13
    Join Date
    Jun 2010
    Location
    Derby
    Beans
    72
    Distro
    Ubuntu

    Talking Re: Grub Error 21

    Quote Originally Posted by grumpy.biatch View Post
    Yeti:

    This is what I got so far -

    ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
    ubuntu@ubuntu:~$ sudo grub-install --root-directory=/mnt /dev/sda
    Installation finished. No error reported.
    ubuntu@ubuntu:~$ sudo umount /mnt
    ubuntu@ubuntu:~$ sudo update-grub
    /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
    ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
    ubuntu@ubuntu:~$ sudo update-grub
    /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).

    Yeti,

    I got in, thanks a bunch.

    Best,

    Dave

  4. #14
    Join Date
    Jul 2010
    Location
    Ontario, Canada
    Beans
    97
    Distro
    Ubuntu 11.04 Natty Narwhal

    Re: Grub Error 21

    Quote Originally Posted by yetiman64 View Post
    Everything seems fine but for
    You will need to Re-install grub to the MBR from the live disk with /dev/sda5 being the root partition.
    From the live disk
    Code:
    sudo mount /dev/sda5 /mnt
    Then
    Code:
    sudo grub-install --root-directory=/mnt /dev/sda
    .
    Then
    Code:
    sudo umount /mnt
    And then reboot the machine, grub menu should come up now.
    Note windows 7 loader is listed in grub.cfg so re-installing grub will also give access to windows. To access an external os later on just plug it in then in 10.04 run
    Code:
    sudo update-grub
    and it should be picked up as bootable by Lucid and added to the menu. To remove from the menu unplug and use the "update-grub" command abve again.

    Edit: this is where i got most of the info http://ubuntuforums.org/showthread.php?t=1195275
    .particularly section 13.
    I know this an old post, but THANK YOU SO MUCH! You saved me a lot of lost work!
    John 3:16

  5. #15
    Join Date
    Jun 2008
    Location
    Narnia
    Beans
    784
    Distro
    Ubuntu 9.04 Jaunty Jackalope

    Re: Grub Error 21

    Many many thanks from me, too.
    Blog
    #!
    Chan eil mi a Gàidhlig agam...pero si hablo español: soy catracho.
    Proud to be a Browncoat!

  6. #16
    Join Date
    Jan 2012
    Beans
    7

    Re: Grub Error 21

    Yetiman, you da MAN!!

    Thankyou so much for the solution.

    I have tried EVERYTHING from Boot Repair CD to command line Boot Repair but it FAILED!

    I was just going to remove Ubuntu for good, when I saw your solution and thought to give it a try and guess what, it worked!

    Thanks agian.

  7. #17
    Join Date
    Jul 2007
    Location
    Magic City of the Plains
    Beans
    Hidden!
    Distro
    Ubuntu Development Release

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •