How To DFU RESET Your Device
NOTE: This process will ERASE ALL THE DATA on your device and reinstall a clean version of the iOS and the Firmware (device radio for Wi-Fi, Bluetooth and Cellular signal.
This is a simple process, but timing is EVERYTHING! If you do not succeed first time, then read through the process again, and then try again. If you fail to enter DFU mode, then we can reset it for you under a diagnostic service for your device.
Ensure that your PC or Mac has the latest version of iTunes installed. This is very important as the install will likely fail if your software is out of date. The latest version can be downloaded directly from the iTunes website here.
Connect your device to your PC or Mac using the USB cable and ensure the computer and your device are powered on.
Here's the tricky timing part, so read through this next step before starting!
OPTION 1: For iPads, iPods and all iPhones up to and including iPhone 6S ...
1: Press and hold the side POWER button AND the front HOME buttons together - 10 SECONDS
2: Release the POWER button but CONTINUE TO HOLD DOWN the front home button.
OPTION 2: For iPhones from iPhone 7 or newer ...
1: Press and hold the side POWER button AND the VOLUME DOWN buttons together - 10 SECONDS
2: Release the POWER button but CONTINUE TO HOLD DOWN the VOLUME DOWN button.