To unlock, you must install the Xposed framework on Android: the installation requires root access, and you have to flash on his camera this framework. This procedure is high risk for the proper functioning of your phone, which could get stuck on startup animation (bootloop). The framework's installation application provided by ImTimer also explains that you should not install this framework if one is afraid of these risks and if we do not know what to do in this case.
These are manipulations reserved for advanced users, and will void the warranty of your smartphone when a software problem. These things should be clarified before the purchase (even for the root password, but having to flash a contraption known to be risked all for a ring, no thank you).
