Factory Reset Protection (FRP) is a security feature introduced by Google on Android devices running Lollipop 5.1 and higher. Designed to protect users in case of theft, FRP requires you to enter the previous Google account credentials after a factory reset. While effective against thieves, this feature often locks out legitimate owners who have forgotten their email or password, purchased a second-hand device, or reset their phone without logging out first.
Improved ADB (Android Debug Bridge) detection ensures the software only activates the "Unlock" button once the device is correctly connected.