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Thread: Boots to grub prompt after installation upgrade

  1. #1
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    Boots to grub prompt after installation upgrade

    I installed 10.04 clean on the PC. Not other operating system. It booted to Ubuntu fine after the install and all appeared to be working fine. Used the upgrade manager to install the upgrades to the basic system. I had not yet loaded in any non-ubuntu or medibuntu repositories so this was the first, basic upgrade.

    After the upgrade, I can no longer boot to Ubuntu but boot to a grub prompt instead. I presume this is a recover prompt. How do I "recover" and continue booting to Ubuntu?

  2. #2
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    Re: Boots to grub prompt after installation upgrade

    https://help.ubuntu.com/community/Gr...0Rescue%20Mode
    Express Boot to the Most Recent Kernel
    Command Summary ls to see drive X & partition Y (hdX,Y) or sdXY:
    ls
    set root=(hdX,Y)
    linux /boot/vmlinuz root=/dev/sdXY ro
    initrd /boot/initrd
    boot

    #show you the available partitions
    ls
    #look for boot files on the partitions
    ls (hd0,1)/boot
    # continue until you see vmlinuz-2.6.xxxx


    Once booted reinstall grub:
    reinstall from working (not liveCD) system - first find Ubuntu drive:
    sudo fdisk -l
    if it's "/dev/sda" then just run:
    sudo grub-install /dev/sda
    If that returns any errors run:
    sudo grub-install --recheck /dev/sda
    Then:
    sudo update-grub
    to get grub to remember where to reinstall on updates:
    sudo dpkg-reconfigure grub-pc
    spacebar to choose drive, enter to accept, do not choose partitions
    Oldfred on vacation. Back Sept 9. Will not have much if any Internet access.
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  3. #3
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    Re: Boots to grub prompt after installation upgrade

    Thanks for the assist but still no joy.

    I was able to get down to the linux command with no errors. However, there is no vmlinuz file or pointer in the boot directory. I was able to enter the latest vmlinuz-2.6.32-23-generic kernel which is what I suspect I upgraded to. The root= command option for linux is unclear. What should the parameters for sdXY be?

    I was able to enter the linux command using sd01 (and later hd01) for the root= option. But the initrd command gave an error of "file not found". Doing ls (hd0,1)/boot/initrd gives file not found".

    If I continue to boot, it will not mount the file system.

    Looks like I know just enough to be dangerous.

    Can you help further?

  4. #4
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    Re: Boots to grub prompt after installation upgrade

    You should have links in the root directory to the most current version of the kernel in /boot. You should be able to check from the liveCD. By using the links it saves typing the exact kernel version. I am not sure if the tab key works in grub, in Ubuntu tab will complete a line if the rest is unique.

    The root command has to be the drive & partition with your install
    (hd0,1) then the install is in sda1
    (hd0,2) sda2
    (hd1,1) sdb1
    etc

    I keep pasting the commands with /boot that should use the links from / (root). If using /boot you do have to enter then entire version.
    Corrected using sda1 or hd0,1

    ls
    set root=(hd0,1)
    linux /vmlinuz root=/dev/sda1 ro
    initrd /initrd
    boot
    Oldfred on vacation. Back Sept 9. Will not have much if any Internet access.
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  5. #5
    Join Date
    Apr 2007
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    Re: Boots to grub prompt after installation upgrade

    Joy, joy, joy.

    It appears that these latter more explicit directions worked. The only command that returned an error was:

    initrd/initrd

    I tried /boot/initrd initrd but that also returned file not found.

    I went ahead and booted anyway and followed the rest of you directions. So far it looks good. I'm going to continue customizing the PC now. Hope all comes out OK.

    Thanks for the help.

  6. #6
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    Re: Boots to grub prompt after installation upgrade

    Quote Originally Posted by oldfred View Post
    I am not sure if the tab key works in grub, in Ubuntu tab will complete a line if the rest is unique.
    It does.
    GRUB2

    Retired.

  7. #7
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    Re: Boots to grub prompt after installation upgrade

    thanks drs305.

    The initrd /initrd should have a space in between.

    Once in your system you may want to reinstall grub to the MBR and update it to see if it works better the next time.

    sudo grub-install /dev/sda
    If that returns any errors run:
    sudo grub-install --recheck /dev/sda
    Then:
    sudo update-grub
    Oldfred on vacation. Back Sept 9. Will not have much if any Internet access.
    For info on UEFI boot install & repair:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  8. #8
    Join Date
    Apr 2007
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    Re: Boots to grub prompt after installation upgrade

    Now, my only question is: How do you mark this thread as SOLVED??

  9. #9
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    dino99 is offline Ubuntu addict and loving it
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    Re: Boots to grub prompt after installation upgrade

    check "thread tools" on top of your first post here

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