I have a Mac Pro 2,1 2x6-Core Xeon@2.66 GHz and am trying to boot from several ISO images written to USB sticks. I have tried the
dd-based methods as recommended by Ubuntu, with no luck. In every case the stick fails to be recognized at boot time. I have also tried booting from a rEFIt CD (which I can do) but the loader there doesn't identify the USB stick in the front of the machine.
Is it possible the MacBooks are so different from the Mac Pros that these instructions wouldn't apply? Does anyone have a reproducible method for creation bootable USB sticks on a Mac Pro and then booting from them?