First things first, you will need:
* 1GB or larger flash drive
* rEFIt (Link at the bottom)
* A linux installation, virtual machine, or live cd
* A Mac OS X installation/installation disk
* Administrator permissions
* gparted (comes on most linux live cd's)
* hfsplus/hfsprogs for hfs+ support in linux
Step one (in linux):
1. Format your USB key with an MBR partiton table.
2. Add an 8MB ext3 partition named "GRUB" for simplicity.
3. Add a 16MB hfs+ partiton.
4. Use the rest of your disk as FAT32.
Step two (also in linux):
1. Mount your ext3 GRUB partiton
2. Open terminal and do "sudo grub-install --root-directory=<mountpoint> /dev/myusb", of couse replacing <mountpoint> with the mount point and myusb with the correct sdX.
3. If you get an error saying that there is no bios boot partition (which you shouldn't), open gparted and select the grub partition and select the flag "bios_grub".
4. Close GParted if it is open and reopen it.
5. Set the boot flag on the GRUB partition.
6. Copy all of the contents of your live cd iso or cd (including the hidden folder ".disk") to your fat partiton.
7. Skip the following steps in the step two if you don't want persistence
8. In terminal create a zero'd out file called casper-rw in the fat partiton with "dd if=/dev/zero of=/media/LIVE/casper-rw". Replace the /media/LIVE with the mountpoint again.
9. Now type "mkfs.ext4 /path/to/casper-rw" and follow the instructions if there are any
Step three (in mac):
1. Open the rEFIt dmg and copy the "efi" folder to the hfs+ partiton.
2. Locate the file called "enable.sh" in the efi folder
3. Open a terminal and type "sudo " and then the path to the enable.sh. (You can find it by dragging the file into the terminal)
1. Reboot your computer holding the option key
2. Select rEFIt on your USB drive (If it doesn't appear take it out and plug it back in or boot all the way up and then reboot again)
3. Select "Linux on HD" that has a picture of a flash drive on it.
4. You will now be at the GRUB prompt, so type the following:
- Code: Select all
linux /casper/vmlinuz boot=casper persistent
Of course take out the persistent part if you didn't use the persistence file.
Ubuntu live cd: http://www.ubuntu.com/desktop/get-ubuntu/download
Original here, thanks to Neds Moar Salt