The wifi signal on my iPhone 4S had been getting worse and worse. At first I thought this was just the distance from my router, but at the same location in the house the reception on my iPad was still 4 bars and on my phone 2 or 1. A web search revealed that deterioration in WiFi reception was a known issue with the iPhone 4S. A couple of articles and forum posts suggested that this was due to an internal screw loosening off.
As my iPhone 4S is coming up for changing and is out of warranty I thought I would have a go at fixing the problem following the suggestions in these various articles.
WARNING:- opening your iPhone will invalidate your warranty so think carefully before you start fiddling.
Fixing the problem involves removing the back and tightening the relevant screw. A simple job one would think. Nothing about an Apple product is ever simple. The back is held in place by 2 pentalobe tamper resistant screws. The chance of have the appropriate screw driver in your kit is remote. They look like a Tork screw but they are quite different. I purchased a kit from Maplins at a cost of £6.99 but you can buy iPhone 4S tool kits on the Internet from a variety of source including Amazon. Warning do not attempt this job without the correct tools.
The first link I found gives a step by step photo sequence for removing the back and getting access tpo the screw in question but unfortunately the most important shot of the screw is misleading, there is no screw! So I have added the image below which clearly shows to screw that needs to be tightened.
IMPORTANT: it is very easy to damage the pentalobe screw slots so be VERY careful when removing and replacing any screw. Make sure the tip of the screw driver is full engaged in the slot. It is also easy to strip threads so do not over-tighten.
Instructions for removing the back of the phone link.
It is a good idea to check the tightness of all the screws you can see. In my phone they were all slightly loose.
NOTE: If you experience wifi problems after having a screen replaced you may find that this screw could be missing completely or more likely the small metal contact that is underneath the screw is missing, see the photo below.
If you want to swap your pentalobe screws for Phillips screws or if you have a problem removing or replacing the pentalobe screws see this article in IFIXIT. Link
Article updated 2.2.14