Bypass the iPhone Passcode Screen
Turn the phone on and go to the Emergency Call screen per the image below.
Image courtesy of: apple
Image courtesy of: macworld.co.uk
Dial any three-digit emergency call number, such as "112" but make sure you do not let the call connect. Hit the end button just before it connects.
Image courtesy of: allaboutappleblog.com
Hitting the Power button will put it in Standby. Turn the phone back on again by hitting the Power button again.
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Continuing to hold the Power button while navigating around your phone to view your contacts and call history.
Image courtesy of: stackoverflow.com
Take a screenshot while simultaneously removing your hand from the Power button. Do this by pressing the Home button and listening for the shutter sound.
Image courtesy of: jailbreakmodo