Restore with Recovery Mode
If the device does not boot or restore process in iTunes does not work, then you have to use the recovery mode to repair the device. For this we must have iTunes open on the computer before.
To enter recovery mode, you must first turn off the device completely. Hold down the power button to turn it off and slid. If the device does not respond, you must press and hold down both the power and home buttons at the same time and for a few seconds until it turns off.
Then the USB device cable connects to the computer with iTunes. Hold down the home button until the screen "Connect to iTunes" appears: you will see a connector pointing to iTunes icon. Now you can release the button. If you do not see this screen and the device starts normally, you need to try again until it does. Just make sure you hold the start button until the display shows:
iTunes will then inform you detected a device in recovery mode. We click on the Restore button and iTunes will restore the operating system of the device.
If neither of these methods solves your problem, then your device has some serious hardware problem, and it would be best to take Apple for review.