Increase the volume of the headphones through the engineering menu

In the Chinese versions of the Flyme firmware the volume is set to maximum, but in the international versions there is a slight limitation. This is done due to passing the certification. However, it is possible to amplify the sound by changing settings in the engineering menu. This only applies to Meizu phones with MediaTek chips.

Enter the engineering menu by dialing the code *#*#3646633#*#*, then Hardware Testing > Audio > Volume > Audio Playback. Select the 3/4-pole headset and set the Heaset PGA to 160. Press Set to save and restart the phone.