Turn the phone on and go to the Emergency Call screen per the image below.
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.
Hitting the Power button will put it in Standby. Turn the phone back on again by hitting the Power button again.
Continuing to hold the Power button while navigating around your phone to view your contacts and call history.
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.