Hold the ''Down'' button and turn on DTR1, do not release the ''Down'' button and you will enter the updating screen. Await for the system to automatically update and restart.
Update log: 1. Modifications on setting page layouts 2. low gain/high gain debug – fixing vol. jump issue during switching 3. non-linear vol. adjustment for fine steps of vol control 4. fixing display of device storage size when there are no card inserted