In order to hard reset a Hisense Sero 8, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Hisense Sero 8 device will be brought back to the default configuration of a brand new device.
2. Now press and hold the Power and Volume Up buttons. Wait for the Hisense /Android logo/Recovery Mode/Boot Mode to appear and let go of them.
3. Enter Recovery Mode by press-holding Power for a while.
4. Using Volume and Power buttons, select the wipe data/factory reset option.
5. Now choose Yes.
6. And now choose reboot system now.
7. Voila, done.