I know this has been discussed over and over but I still cannot run Ubuntu on a USB stick.
Here's the step I followed:
1. I downloaded Ubuntu 12.10 (ubuntu-12.10-desktop-i386.iso) from http://www.ubuntu.com/download/desktop which I renamed 'ubuntu.iso'. I bought my Mac mid-2010, it has an Intel processor.
2. I formated my 16GB USB stick with HFS+ File System following this tutorial: http://www.switchingtomac.com/tutorials/how-to-format-a-drive-or-partition-with-the-hfs-file-system
3. I opened a terminal and typed: hdiutil convert -format UDRW -o ~/Downloads/ubuntu.img ~/Downloads/ubuntu.iso
It created ubuntu.iso.dmg
4. I ran 'diskutil list' and identified the device node assigned to the USB.
5. I unmounted it: diskutil unmountDisk /dev/disk2
6. Then, I entered the command: sudo dd if=~/Downloads/ubuntu.img.dmg of=/dev/rdisk2 bs=1m. It seemed to work. A Mac message poped up saying that the system doesn't recognized the disk, I pressed 'ignore'.
7. I ejected the USB using diskutil eject /dev/disk2, then removed the USB.
8. I rebooted the computer, plugged the USB key, pressed ALT.I could see my Macintosh partition and my Windows partition, but couldn't see my USB stick.
Any help will be very appreciated :)
Victor