Answer

Entering the test mode

Under the power-on state, press and hold the “middle key” for about 10 seconds until the red light flashes. Then press and hold both the “middle key” and the “right key” for 5 seconds to enter the test mode.

Test contents

The default screen backlight remains on, and all icons on the screen are displayed. The red, orange, and green lights are off by default. Short-pressing either the “left key” or the “right key” tests the following in sequence: buzzer sound, vibration, red light, orange light, green light, and screen display.

Exiting the test mode

To exit the test mode, short-press the “middle key”. Under the power-off state, the device will be restored to factory settings and enters complete power-off mode.