USB and CD/DVD use different filesystem standards, thus you need to format your ISO for the correct storage medium. If you dd or copy a CD/DVD ISO image to your USB, it may not work. You can get around this by using the ISO hybrid command. Try these steps. 0) isohybrid /path/to/image.iso 1) plug your USB device in 2) find the device your USB shows up as (/dev/sd{a,b,...}. You can use the df -h command for this 3) unmount your USB drive umount /dev/sd{a,b,...} 4) write the ISO to your USB device dd if=/path/to/image.iso of=/dev/sd{a,b,...} bs=4M 5) your ISO should now be bootable on on your USB. --Timothy Pulliam