Hello. I had an iphone 4 that my aunt had dropped and shattered the screen. I was mad but then i remembered i had an old 4s that had a good screen. I removed the screen from both devices and got a heat gun to remove the bezels. After i removed them i stwiched them and removed the built in home button from the 4s screen and put the screen on the iphone 4. After i got the phone all together, i powered it up and it worked perfectly except one little unnoticeable line in the lock screen. My suggestion is to unplug all the cables for the screen and make sure there are no defects on the wire. If there is no defects restore the phone because when you change screens on older devices, the screen sometimes lights up white. Good luck!