This question gets asked a lot, especially since people are having non-functioning keyboards in Linux Bootloaders (Windows too). If you make room on your Intel Mac to boot Windows and Linux, most distros will now detect windows and add an entry to grub and/or lilo, and install the bootloader to the MBR (Master Boot Record) of your disk. This is ok on most PCs, as there is not normally any other way to choose which OS you want when booting up. However, most Mactel multibooters are using rEFIt to select the OS, and there is no need to use grub for anything but Linux (and hopefully, a EFI native bootloader will be available someday to replace that).

The way to get around this annoyance is to install your Linux bootloader to the root partition (or your /boot partition if you have one), and leave the normal Windows bootloader in the MBR. I use Ubuntu and Grub, and will focus there, but these general instructions should work for any system.

New Linux install

I am not going to detail the process to install Windows. There is more than one method, the easiest probably being to use Bootcamp.

Most Distros will allow you to edit where to install your bootloader somewhere. I use Ubuntu, so I want to let know know where to make this change when installing Ubuntu. After running the installer, creating your Linux partitions, etc, the last screen before it actually installs gives a summary of what you are going to do. There is a button in the corner labeled “Advanced” clicking on that will give you the opportunity to specify where to install grub. You will want to make sure you use the partition that is for your root filesystem (/). If you have created a separate /boot partition, you will want to install it there.

After you install the Linux OS system, and you reboot, there should be 3 icons in rEFIt. One for OSX, one for Windows, and one for Linux. Choosing the OSX or Windows icons will boot directly to that operating system, and choosing Linux, will start your chosen bootloader. If you don’t want to see the bootlaoder at all, then you can edit the config file to reduce the delay (although I would keep some sort of delay in case you needed to switch to another kernel or something.)

I’ve already messed up and installed to the MBR!

It’s OK, you can fix it!

Put The Linux Bootloader in the Correct Location

Boot into your linux system (or if you are not able to boot linux, boot a live cd) and open a terminal. You will start the grub command line. You will need root permissions:

sudo grub

You will then be at the grub command line. You will then want to find where your grub config file is and such by issuing the command:

find /boot/grub/stage1

If that does not work, try this instead:

find /grub/stage1

This will return a harddrive/partition designation of the form (hdx,y), where x is the number of the hard drive, and y is the number of the partition. Grub counts from zero though, and doesn’t differentiate between hd and sd type hard drive designations. So, some examples of the normal /dev name and the grub name:

• hda = (hd0)
• hda1 = (hd0,0)
• sdb1 = (hd1,0)
• sdf4 = (hd5,3)

NOTE, that on some systems, hda does not translate to (hd0) as expected for some reason. This is primarily evident on Mac Pros that have multiple hard drives. Be sure to try the find statements above first. (This is also seen in some machines where the CD/DVD drives are recognized as hda, hdb, etc.)

Using the result of the above information, you need to set the ‘root’ (where grub’s files are), then install grub to the appropriate location:

grub> root (hdX,Y)

grub> setup (hdX,Y)

grub> quit

Be sure you replace the X and Y with the correct numbers of your partition.

Fixing The Windows Bootloader (Replacing the MBR).

After that, your Linux bootloader is in the correct location, and we now need to fix the Windows bootloader. Fortunately, Microsoft gives you a tool to do this with each copy of windows. You will need to boot your Mac from your Windows install CD into the “Recovery Console”. Once you are at the prompt, simply run:

fixmbr

Now, you can reboot. You should have 3 icons in rEFIt, and each works as mentioned above!

Reference:

1. Windows XP Professional Product Documentation
2. GNU GRUB manual 0.97

This entry was posted on Wednesday, October 31st, 2007 at 11:35 AM and is filed under Apple, Computers, Linux, Ubuntu, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.