A dropped my iPhone 6S a while ago and cracked the screen but never got around to getting it repaired unfortunately. Last time I went out and must have dropped it again as there are now 3 thin black lines running top to bottom on my screen. The phone still works perfectly. Options. There are a number of reasons why some iPhone 6 screens usually replacement ones have either yellow, blue, or dark spots on the screen or edges of screen: - White dots on screen pressure marks usually caused by debris, screw behind backplate or under screen. - Huge pressure mark, screen been forced in with dented inward metal housing The answer is yes, there's a black border. ( 0) Reply. of 1. My iPhone 6s has black border lines around the screen. Is this normal? tfPQ.