Maybe this is a silly question, but I tried to mount a 4GB Fat32-formatted USB stick which has been inserted in the free USB-Port of the Arduino Board. The board is powered via a micro USB cable. dmesg | tail shows absolutely no message, therefore I need some advice about what might be wrong.
Only one of those two usb ports can be active at once, as specified by the micro switch between the ports. In order to use the larger USB port, you need to power via barrel jack socket, and move the switch towards the larger usb port.