Use the following procedure to format an external USB flash drive on the F-20:
1. Connect the USB flash drive that you want to format to the USB MEMORY port.
2. While holding down the SONG button, turn the power on. Keep holding down SONG button for at least six seconds.
The OTHER button and the SPLIT button will blink.
3. To execute the format, press the SPLIT button. To cancel, press the OTHER button.
When all the LEDs on the buttons are lit, the operation is complete.
4. Turn the power off, then on again.