Knock on is an LG feature that enables you to turn on the screen with just two taps. To avoid relying on the iPhone's Power button, you can learn how to use the knock on feature on iPhone 6, IP 5s, 5, 4s below.
Using Knock On on iPhone 6, IP 5s, 5, 4s
Step 1: To begin, access Cydia, then search for the tool named SmartTap and install it.
Step 2: After installation, open SmartTap, find the Enabled option, and switch it ON.
Those are two simple steps to help you utilize the knock on feature on your iPhone 6, IP 5s, 5, 4s. Of course, your phone needs to be jailbroken to use this feature. Additionally, refer to the trick of changing iPhone 6 battery icon to angel wings for more details.
