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I recently installed Ubuntu 9.10 on my macbook, hoping to create a dual boot system... I use rEFIt to boot.

Installation went great, up until insatllation of grub. Trying to create a dual boot system, I have a handful of partitions, and Ubuntu didn't ask where to put grub; it just choose a partition and put it there.

In the past, Debian worked well with grub and Debian in the same partition. (Debian, macbook and drivers is a high-maintenance trilogy, though...)

This is what Partition Inspector says:

*** Report for internal hard disk ***

Current GPT partition table:
 #      Start LBA      End LBA  Type
 1             40       409639  EFI System (FAT)
 2         409640    332556807  Mac OS X HFS+
 3      332820480    391414229  EFI System (FAT)
 4      391414230    440242355  Basic Data
 5      440242356    476678383  Basic Data
 6      476678384    488397134  Linux Swap

Current MBR partition table:
 # A    Start LBA      End LBA  Type
 1              1       409639  ee  EFI Protective
 2 *       409640    332556807  af  Mac OS X HFS+
 3      332820480    391414229  83  Linux
 4      391414230    440242355  83  Linux

MBR contents:
 Boot Code: Unknown, but bootable

Partition at LBA 40:
 Boot Code: None (Non-system disk message)
 File System: FAT32
 Listed in GPT as partition 1, type EFI System (FAT)

Partition at LBA 409640:
 Boot Code: None
 File System: HFS Extended (HFS+)
 Listed in GPT as partition 2, type Mac OS X HFS+
 Listed in MBR as partition 2, type af  Mac OS X HFS+, active

Partition at LBA 332820480:
 Boot Code: None
 File System: ext3
 Listed in GPT as partition 3, type EFI System (FAT)
 Listed in MBR as partition 3, type 83  Linux

Partition at LBA 391414230:
 Boot Code: None
 File System: ext3
 Listed in GPT as partition 4, type Basic Data
 Listed in MBR as partition 4, type 83  Linux

Partition at LBA 440242356:
 Boot Code: None (Non-system disk message)
 File System: FAT32
 Listed in GPT as partition 5, type Basic Data

Partition at LBA 476678384:
 Boot Code: None
 File System: Unknown
 Listed in GPT as partition 6, type Linux Swap

I'm pretty sure grub was put in GPT #3. I want it to be in GPT #4, where Ubuntu is. How do I move it, ie. do the old uninstall/install?

LiveUSB? LiveCD? What do I write in Terminal...?

Cheers!

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1 Answer

up vote 2 down vote accepted

There's a good Grub 2 Guide on Ubuntu Forums; this is what I used during my recent Grub2 adventure. Here's another good Grub2 guide, and Ubuntu's Grub2 wiki page.

  1. You "uninstall" Grub from a partition by overwriting the boot code it wrote into the boot sector of that partition. Ideally, you'd have a backup of what was there before Grub was installed to it. I don't believe Grub creates this backup for you, so if you want something particular there (other than Grub), you'll need another tool to provide it.

    If you want, you can completely uninstall the Grub package, then reinstall (I doubt this is necessary). To do this from a LiveCD system you'll need to chroot into the system you're trying to fix.

    # chroot (assumes you've mounted the partition to fix to /mnt)
    sudo mount --bind /dev /mnt/dev
    sudo chroot /mnt
    
    
    # backup!
    cp /etc/default/grub /etc/default/grub.old
    cp -R /etc/grub.d /etc/grub.d.old
    cp -R /boot/grub /boot/grub.old
    
    
    # purge
    apt-get purge grub2 grub-pc
    
    
    # reinstall
    apt-get install grub2 grub-pc
    
    
    # grub install -- make sure /dev/sda is the right drive!!
    grub-install /dev/sda4
    update-grub
    


    If everything went well, you can exit your chroot, unmount your filesystems (/mnt/dev first), and reboot.

  2. If all you need to do is install Grub to the correct partition, all you really need to do is boot into a LiveCD/LiveUSB, mount your system partition, check that your system's /boot/grub is correctly set, and run grub-setup. If you need to reconfigure the Grub menu or perform other steps, use a chroot procedure as described earlier.

    Let's assume you've booted the LiveCD and mounted your system drive to /mnt. Check that /mnt/boot/grub exists, and contains the proper files (a bunch of *.mod files, a few .img files, and grub.cfg). If so, run this (not from chroot):

    # install grub to partition boot sector on sda4
    #    this assumes the partition table you show is on /dev/sda
    #    make sure path & device are correct !!!
    sudo grub-setup -d /mnt/boot/grub /dev/sda4
    


    (Source: Re-install GRUB 2 from a Live CD without chroot)

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Excellent! The second option is what I was looking for. –  trolle3000 Feb 5 '10 at 4:45
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