In iTunes, you should see the iPhone appear in Devices. Click it to see a window saying iPhone Recovery Mode with the message: "If you are experiencing problems with your iPhone, you can restore its original settings by clicking Restore iPhone." Click Restore iPhone.
How to exit DFU mode on the iPhone
Exiting DFU Mode and returning to normal mode is easy enough. Simply hold both the Home button and the Sleep/Wake button until the Apple logo appears.
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