I will describe a few simple steps to perform a hard reset on the Meizu MX4.
Option 1:
1) Turn off the device if it is turned on.
2) Hold down two buttons simultaneously: power button and volume up, hold until “flash mode” appears. If it does not work, then you need to hold down the power and volume buttons down.
3) In the menu that appears, pressing the volume buttons highlight the item “System Upgrade and Clear Data” and select it by pressing the power button. Next, select “Start” in a similar way.
4) Upon completion of cleaning, the device will automatically reboot.
Option 2:
1) Turn off the device if it is turned on.
2) Press the buttons simultaneously: turn on and go home, hold for about 10 seconds.
3) Wait for the device to reset.