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I want to install ubuntu , without it touching my MBR. I plan to install ubuntu 12.04 on a particular ext3 partition and grub on the PBR of that partition.

From this page:

If you have a problem with changing the MBR code, you might prefer to just install the code for pointing to GRUB to the first sector of your Ubuntu partition instead. If you do that during the Ubuntu installation process, then Ubuntu won't boot until you configure some other boot manager to point to Ubuntu's boot sector.

So it tell me what I have to do. My question is how do I do this ? I am guessing I have to

  1. grab the alternate install disc
  2. choose manual partitioning
  3. it will ask me to install grub and I have to choose the partition instead of the MBR .
  4. edit boot.ini to add ubuntu . I am on xp.

Are these steps correct ? Please tell , I am asking because I really don't want to screw this up. Also are there any other gotachas I should keep in mind ? Like updating screwing up the MBR ?


Edit: One question: in the alternate install CD , where exactly is the option to install grub in PBR ?

Edit2: why does anything I am trying to do has a bug associated wit it .

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You can install Grub to a partition boot record even with the Desktop CD!

Just choose manual partitioning, and choose to install the bootloader to /dev/sdaN.

The XP bootloader (NTLDR) will not chainload Grub2 by default.

Note that NTLDR will NOT chainload Grub2 by default. You will need an intermediary such as Grub4DOS (recommended), or create a Grub2 stub for NTLDR.

A downside of installing Grub2 to a PBR

When installed to a PBR, Grub2 is very sensitive to moving/resizing the partition; you will need to reinstall it from a Live-CD/Live-USB if you do that.

The easiest alternative: a boot manager such as Plop

Personally, I recommend the Plop! Boot Manager as a tiny, pain-free way to get this working without having to mess with boot.ini, etc. It basically gives you a menu at bootup allowing you to choose a primary or logical partition to boot from.

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can grub be used instead of grub2 ? – gyaani_guy Jul 4 '12 at 14:00

Yes. Those are correct steps.

However you might have problem while adding boot menu entry in XP. If you were in windows vista or 7 EasyBCD can do this very easily.

Here is an answer that might help you though it suggests downgrading of grub 2

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So all I have to do is make sure I install grub instead of grub2, which the alternate install disc allows ? – gyaani_guy Jul 4 '12 at 11:43

Yes, these steps are correct (and you can also do it from a standard Ubuntu CD).

You may also want to first create a backup of your MBR and partition table. This can be done easily via Boot-Repair -> Advanced options -> "Backup the partition tables, boot sectors..".

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