How To Dual Boot OS X and Linux

By | 2011/06/14

How to dual boot OS X and Linux. Works on any Intel Mac with any version of Linux!

Note: rEFIt does not work with 10.7 Lion yet (step 4). Wait for an rEFIt update before attempting on a 10.7 machine.

Warning: This is scary stuff – you can really trash your system and data! I am not responsible if any problems occur. Always backup your data!

1. Backup your entire existing OS X hard drive onto an external drive using a utility such as Carbon Copy Cloner. This is a CYA step!


2. Create a Boot Camp partition using the Boot Camp Assistant. I’m creating a 60GB partition for Linux Mint in this example.


3. Reboot, make sure all is well with OS X after the Boot Camp partition change.

4. Install rEFIt and then reboot twice to make sure it is installed and working ok. (Hold down option at boot to see rEFIt menu if it does not appear automatically.)


5. Boot your desired Linux install CD/DVD by holding down ‘C’.


6. Install Linux as normal to the Boot Camp partition. It is critical to _delete_ the Boot Camp-made Fat32 partition for Windows and replace it by creating a root (/) and swap partition for your Linux install.


Another critical step: the bootloader (grub) should be installed to the Linux root partition, and not the MBR/EFI part of your hard drive. You must make this change in your Linux install! In this example, the Linux boot loader is being installed to /dev/sda3.


7. After the Linux install completes, fully shutdown the computer. (Apple ‘reboots’ are at times very soft reboots that sometimes do not cut it.)

8. Turn the machine back on. From the rEFIt menu, you can now choose and boot into Linux or OS X!

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Notes: If Apple complains that it cannot create a boot partition, try booting from an OS X install CD, run Disk Utility, and click Repair Disk. The go back into OS X and try the Boot Camp Assistant again.

If you ever want to remove rEFIt, simply go to the OS X Startup Disk Preferences, and choose your OS X Hard Drive as the startup disk. This ‘click’ will overwrite and remove rEFIt.

Grub is optional – you actually can skip installing a bootloader if needed. rEFIt will just dump you right into Linux. However the recovery options that grub provides are worth keeping, IMO.

rEFIt has trouble booting to a second internal hard drive. If you are attempting this, be aware of this as an issue in their FAQs.

As seen before, Linux beats OS X on the same hardware in identical cross platform benchmarks!