In this situation, you need to either do a master reset, or to find firmware for your device and re-ask. Thus all the user data in memory will be deleted.
Regarding the total discharge it under your model - no information. But you can follow the general guidelines:
Turn off your device. You need to get in rekaveri menu. Typically this is achieved by simultaneously pressing several (usually 3, but may be two) keys: volume keys, menus, and inclusion. Try different combinations of their own.
When you see the rekaveri menu, find and select the item Wipe data / Factory Setting. Then confirm Yes - delete all data. Then select Reboot.
P.S. If you have picked up on our board combination to enter the rekaveri, please share these keys so that other users can easily use them.