Hard Reset PHILIPS S399

At the very beginning power off the handset.
Afterwards press and hold the Volume Up button.
While holding Volume Up press the Power button for a short while.
Release held keys when you see an Andoid image.
Press the Power button to enter Recovery Mode.
Afterwards press Volume Down to choose "wipe data/factory reset", and then push the Volume Up button to confirm.
Choose "Yes--delete all user data".
To restart the phone, select "reboot system now".
That's all! The factory reset has just been done.