GP2X built in USB host port

The GP2X is an handheld running Linux. It has 2 arm-processors and a few peripherials, amongst others an usb host function. The usb host function is available through the ext-port, but no 5V is available there, so in order to get usb from that you'll either need a wall wart to supply the 5V or use a DC-DC-converter to generate 5V from the 3.3V that is available from the ext-port.