When I try boot the USB from bios into ubuntu 12.10 it just comes to a menu with a black screen and a couple lines of text. There is no option to run from USB even though I have persistence enabled.
Here's a picture of the screen:
I don't know why the menu looks exactly like it does, but a live USB flash drive, even with a persistent area, still provides the same boot options as a normal live USB flash drive with no persistent area.
So, to use the system on the USB drive, select Try Ubuntu without installing. It should work fine.
In case something went wrong in the creation of the live USB, I recommend testing its persistence first before assuming it works. For example, you could create a file on your desktop. Then shut down and reboot, and see if the file is still there. If it is, you should be good to go.
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