SHP-DH538 - How to perform a factory reset

1. Unlock and open the door
2. Take the battery cover off
3. Press and hold the [REG] button for 5 seconds : Ding Dong -> Ding Dong
4. Enter the factory reset code + *
   • 4560852580 : Factory reset without wireless module connection
   • 1470852369 : Factory reset including wireless module connection
   • Success : Ding Dong Deng
   • Fail : Dingdongdingdong