Karbonn Smart A51 Plus Hard Reset:
1. Charge the battery 100 percent.
2. Turn off your Karbonn Android phone.
3. Turn ON the device by pressing and holding the VOLUME UP key and the power key together.
4. Boot Mode will appear, Select recovery mode and press volume down to enter.
5. After it, Android Logo with exclamation mark appears.
6. Press Power key to enter recovery mode.
7. Select wipe data/Factory reset using volume key.
8. Select Yes-delete all user data.
9. Hard reset is done switch ON the mobile.