Adjust your locked iPhone's volume
You lock your iPhone to keep your private data and Angry Birds high scores from prying eyes. But suppose you're walking into a noisy party where you'd prefer to turn the volume up, or you're attending the State of the Union address and want to dial the volume down a bit as you enter the House of Representatives. If you're focused on conserving energy and finger swipes, Hints reader Coumerelli discovered a simple way to adjust your locked iPhone's volume without entering your passcode first.
Wake up your iPhone—either with the Home button or the Sleep/Wake button. On the Enter Passcode screen, tap the Emergency Call button. Now, instead of dialing the local police, press your volume rockers instead. From that Emergency Call screen, you can adjust the volume of your otherwise-locked iPhone.