Installing rEFIt on the system partition, instead of using Mac OS X system volume, allows one to manage rEFIt independently from Mac OS X. It is also possible to wipe out Mac OS X entirely while still being able to use rEFIt to boot other operating systems, like GNU/Linux, FreeBSD, Solaris, or even Windows.
From a Terminal or command-line prompt, run the following commands:
$ sudo mkdir /efi
This will create the mount point for the EFI system partition
$ sudo mount -t msdos /dev/disk0s1 /efi
This command will mount the EFI system partition (usually hidden from Mac OS X) into /efi. The EFI system partition is basically a 200MB FAT32 partition which is, by default empty.
Note: Please, take into consideration that EFI system partition is usually the first partition on the built-in hard disk, which is usually /dev/disk0s1, although it could be different on your system.
This will open the /efi folder in Finder.
Now, download rEFIt and copy the contents of the efi folder into /efi.
In the end, you should have the following subdirectories on your machine:
Now, we will bless the EFI system partition:
sudo bless --mount /efi --setBoot --file /efi/efi/refit/refit.efi --labelfile /efi/efi/refit/refit.vollabel
That's pretty much it. Now just reboot and enjoy rEFIt.