Someone has uncovered a security bug in Apple’s iOS 4.1 that allows you to bypass the phone’s security lock to make calls. From phone’s locked screen, press the “Emergency Call” button, dial a non-emergency number such as “###”, then hit the call button and quickly press the “Wake/Sleep” button on top left of the phone. This will bring you to the phone app where you can cancel the call to “###”, access the contacts, and dial or sms a different number. This bug however does not allow you to reach the home screen to access other app.
This bug affects iPhone 4 only and appears even in the latest iOS 4.2 beta. Let’s hope a fix is coming soon from Apple.