Flashing a stock FTF with a full is the only reliable way to remove a forgotten screen lock on the Sony G3311. This restores the phone to an unlocked, out-of-box state (subject to Google FRP verification).
, requiring the Google account previously synced to the device to finish setup. FRP bypass steps sony g3311 lock remove ftf
Open Flashtool, click the icon, and select Flashmode . Flashing a stock FTF with a full is