Power off before remove the Battery. Undo 2 Screws with PH#000 Screwdriver. Remove Complete Front Screen Assembly with Guitar Pick. Move back and forth. Be careful and patient. Do the same in the other side. Put the Complete Front Screen Assembly aside. Remove the little piece with Tweezer. Remove the worn Headphone Jack Flex with Tweezer. On the right is the worn Headphone Jack Flex. Left is the new. Under the Plastic Film they are the same. Install a new Headphone Jack Flex with Tweezer. Press it with Plastic Spudger or other plastic things. Put back the little piece. Start from the top of the back cover will be easier. Press from top to the bottom. Tighten these 2 Screws with PH#000 Screwdriver. Power on. Plug in with Headphone. Play a music. Check whether the quality is same as before. To see if problem has been resolved.