Reset your iPhone
- Hold and press the power button on your iPhone.
- Wait for the power slider to appear on your screen and when it does, drag it to the end of the screen and the iPhone will be turned off.
- Wait for a few seconds and turn the iPhone back on.
Enter your iPhone into DFU Mode /Recovery Mode to try again
- Connect device to your computer and launch iTunes.
- Turn the device off.
- Hold and press the power and home buttons together until the Recovery Screen appears. Then update your iPhone with iTunes.
- Connect the device to the computer and launch iTunes.
- Press and hold the power and home buttons together for 10 seconds.
- After, release the power button and just hold the home button for 5 more seconds. The screen will go completely black. Then update iPhone with iTunes.