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Grub booting problem

  • 15-12-2007 9:08pm
    #1
    Stky10
    Registered Users, Registered Users 2 Posts: 1,165 ✭✭✭


    I've bought an external HD for my laptop. The internal HD runs WinXP, but I've installed Ubuntu 7.10 on the external disk.

    Problem is that now when I boot the machine, it reads the MBR from the internal disk, and then loads GRUB from the external HD. But that means I always now have to have the external disk connected when I want to reboot or else it gives me a GRUB error.

    Whats the best way round this?

    - Create a small partition on the internal HD and have the GRUB configuration there?. If so, what format would the partition be (ext?), and does it have to be at the beginning of the disk, or can it just be at the end?

    - Repair the MBR on the internal HD to be of standard windows format, so that it reads then reads boot.ini within the windows partition and gives me an option of loading either Windows or Ubuntu. Something along the lines of

    [boot loader]
    timeout=30
    default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
    [operating systems]
    multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=alwaysoff
    multi(0)disk(1)rdisk(0)partition(1)="Ubuntu Desktop 7.10" /noexecute=alwaysoff

    - Or other?


Comments

  • #2
    AndrewMc
    Registered Users, Registered Users 2 Posts: 354 ✭✭AndrewMc


    Stky10 wrote: »
    - Create a small partition on the internal HD and have the GRUB configuration there?. If so, what format would the partition be (ext?), and does it have to be at the beginning of the disk, or can it just be at the end?

    It almost certainly needs to be in some sort of Linux format, ext3 would be fine. I think the partition can be anywhere on the disk these days. A nice round number would be about 100MB or a bit more to cover multiple kernels for the next while.
    Stky10 wrote: »
    - Repair the MBR on the internal HD to be of standard windows format, so that it reads then reads boot.ini within the windows partition and gives me an option of loading either Windows or Ubuntu. Something along the lines of

    [boot loader]
    timeout=30
    default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
    [operating systems]
    multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=alwaysoff
    multi(0)disk(1)rdisk(0)partition(1)="Ubuntu Desktop 7.10" /noexecute=alwaysoff

    I've no idea how the Windows boot loader works, unfortunately. If using this approach you selected Ubuntu, would it go to the external drive and start Grub again? If so, this would make booting a two-step approach, whereas keeping grub (and a small /boot on the internal drive), would mean one boot loader booting either in one step, if you get what I mean.


  • #3
    joe_chicken
    Registered Users, Registered Users 2 Posts: 1,287 ✭✭✭joe_chicken


    Stky10 wrote: »
    - Repair the MBR on the internal HD to be of standard windows format, so that it reads then reads boot.ini within the windows partition and gives me an option of loading either Windows or Ubuntu.

    This is the best option, it sounds like the windows MBR was corrupted during the Ubuntu install...

    I have Ubuntu on a SATA hard drive that I turn off/on in the BIOS.

    I have it setup as the master when it's on, so it uses GRUB to boot either Windows or Ubuntu. When it's off it just boots to windows.

    After fixing the MBR I'd unplug the internal hard drive and do a fresh install of Ubuntu on the external one. Then plug the internal one back in and set the hard drive with Ubuntu as master, then you can configure it to boot to windows.


  • #4
    Voodu Child
    Closed Accounts Posts: 6,706 ✭✭✭Voodu Child


    Google 'grub error 21 external HD' and you should find a solution.

    It seems to happen to everyone who tries to install ubuntu to an external HD and follows the default prompts.

    I havent gotten around to looking for the quickest solution (I just restored the MBR myself and havent bothered with ubuntu since), but that google search should throw something up.


  • #5
    Stky10
    Registered Users, Registered Users 2 Posts: 1,165 ✭✭✭Stky10


    Thanks, I've fixed the MBR with a windows xp cd, and I think I should be able to work it from either one of

    http://www.matthewjmiller.net/howtos/dual-boot-linux-and-windows/

    http://ubuntuforums.org/showthread.php?t=87751

    Then I need to figure out how to get it to work with my 3 Mobile Broadband modem. The joys....


  • #6
    jimmyjim11
    Registered Users Posts: 257 ✭✭jimmyjim11


    Stky10 wrote: »
    Thanks, I've fixed the MBR with a windows xp cd, and I think I should be able to work it from either one of

    http://www.matthewjmiller.net/howtos/dual-boot-linux-and-windows/

    http://ubuntuforums.org/showthread.php?t=87751

    Then I need to figure out how to get it to work with my 3 Mobile Broadband modem. The joys....

    this should help with 3g modem ;)
    http://www.linux.ie/articles/tutorials/threeirelandUSBmodem.php


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