1. Find the two only need the top of the audio key "on / off" and "+". As shown in the picture:
2. Press and hold the above two keys with two fingers at the same time, special pass attention is to press and hold at the same time. As shown in the picture:
3. Press for a long time, about 20 seconds. As shown in the picture:
4. Then press the two keys for tens of seconds, the stereo will be set to the initial state, you can use it normally. As shown in the picture: