In order to hard reset a Helio Mysto, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Helio Mysto device will be brought back to the default configuration of a brand new device.
1. Power up the phone.
2. Open Menu. Now go to Customize > Settings > Device.
3. Enter the password, 0000 or the last 4 digits of your phone number by default.
4. Now select Reset > Reset Defaults and Yes.
5. Confirm with a thumb key.