How to enter Lenovo A3900 Recovery Mode and Hard Reset.
- Turn off the device
- Press and hold Volume UP key + Power Key
- Release all key when you see Android logo
- Press Power key to Enter Recovery Mode
- Use Volume down to scroll and Volume Up key to confirm
Hard reset Lenovo A3900
- In Recovery Mode select wipe data / factory reset
- press Volume up key to confirm
- select Yes — delete all user data, press Volume up key to confirm
- select Reboot system now to finish hard reset
Warning! Make sure to back up your important data. The data can not be recovered after perform a hard reset.