The iPhone has a variety of passcode features to help protect the device from prying eyes. Normally with a four-digit "simple" passcode, the iPhone unlocks as soon as the fourth number is entered. iOS users can set a complex passcode which includes letters, however when this is enabled an OK button appears. From then on, unlocking the device requires tapping an OK button after entering the password.
Now jailbroken iPhone users who use a complex passcode can skip the OK button with the free tweak AutoOk installed. Just as it's named, the tweak will automatically register the passcode OK button, making complex passcodes behave like simple passcode entry. As soon as the full password is entered the device will unlock.
This can save time and energy if the iPhone is set to enable a passcode quickly for increased security. When it comes to AutoOk, the tweak will automatically disable if the complex passcode entered is incorrect. Once installed, AutoOk must be configured and enabled in the Settings. Simply enter the complex passcode that is used on the lock screen into Settings -> AutoOk -> Password then select Enabled -> ON. From now on, the OK button on the lock screen will be skipped.
AutoOk is available on Cydia from the BigBoss repo free of charge. Check here for instructions on how to jailbreak iOS 6.x with evasi0n. You can also find out how to purchase and install Cydia tweaks with this guide.