Chosen Solution
I just reassembled my iphone 4s and have this left over. Doh! Can anyone tell me where it goes?
That is the cover of the WiFi antenna cap. The red circle is over its screw which threads into the underlying stand-off screw. https://d3nevzfk7ii3be.cloudfront.net/ig…
It’s for fastening the motor vibrator. Did your vibrator work normally?
