USB drive takes the drive letter A:\ in EZ Flash 2. You can choose it with the Tab key.
Thanks for the reply - I'm not able to run EZ Flash though - whether by a) running it with Alt + F2 (it doesn't load/detect the USB drive) or b) selecting it through BIOS/Tools (no option to).
BIOS does pick up the USB drive though, as it appears in the connected peripheral list.
Very confusing :-(