I upgraded my operating system on my 4s to 6 & now I cannot access my wi-fi button as it is greyed out, it has
also affected my icloud backup, same thing its greyed out.
I went into my local Apple Store & they told me that they had never heard of this problem, they then told me
to connect to itunes & do a complete restore of my iphone, I have done this but its still the same, can anyone please assist?
It gave you several troubleshooting steps to try, which sometimes work.
However, in many if not most cases, this is due to a hardware failure. Updating and restoring the phone is stressful to the device, and can cause marginally functioning components (such as the WiFi chip) to fail. In that case, replacement will be your only option.