Use this guide to replace the back cover of your Huawei Mate 9 smartphone.
First switch off your phone and remove the SIM card tray.
Remove both screws on the bottom with a Torx T2 screwdriver.
Use a plastic opening tool to get between the display and the case. Open the smartphone by carefully prying out the display with all the parts out of the case.
Swing open the phone to the right side.
Disconnect the fingerprint sensor cable with a spudger.