WARNING! When you factory reset your device, all data stored on the phone’s internal memory will be deleted, including apps, contacts, ringtones, downloaded content etc. Furthermore, all settings will be restored to factory values.

NOTE: Before you factory reset your phone, you can visit this thread for instructions on how to back up personal data, and this thread for instructions on restoring personal data. You can also visit this thread for additional backup & restore options via Google Drive or locally.

Factory Reset via Settings:

  1. Tap “Apps” on the home screen
  2. Open “Settings
  3. Tap “Backup & Reset” > “Reset phone
  4. Optionally, enable or disable “Erase SD Card” (WARNING! When you enable this option, all data stored on the SD card will be deleted during the factory reset process)
  5. Tap “OK” to confirm

Factory Reset via Recovery (Hardware Buttons):

NOTE: If your phone freezes, crashes, or otherwise prevents you from resetting it via Settings as described above, you can try resetting the device from the Recovery menu which can be accessed by performing a combination of button presses as explained below:

  1. Press and hold “Power” to turn off the phone
  2. Next, press and hold “Power” and “Volume Down” at the same time
  3. When you see three Androids on the screen, release all hardware buttons
  4. You should now have access to the “HBOOT” menu. If so, press “Volume down” repeatedly to highlight “Factory reset
  5. Press “Power” to confirm and select the highlighted option
  6. Wait for the phone to factory reset. Once done, reboot your phone at the prompt to complete the process

Check for Firmware Updates:

NOTE: After a factory reset it’s recommended to verify if new software updates are available for download. To do this:

  1. Open “Apps” on the home screen
  2. Go to “Settings
  3. Scroll to “Phone
  4. Tap “About” > “Software information
  5. Verify if a new OS version is available for download. If so, follow the on-screen steps to complete the update (this process will require you to restart your phone)

See More: HTC One A9s: Factory Reset and Check for OS Updates