OK I have found a solution on the internet and it worked for me and for two other phones with the same problem.
⚠ Let me state this clear: I would have never tried anything like this, I followed this solution because I tried ANYTHING (hard and soft resets, icloud password resets and other stuff), and because Apple asked me money to fix the phone while IT IS CLEAR THAT THE PROBLEM IS IN NO WAY CAUSED BY MY USE OF THE PHONE, I just upgraded the iOS OTA (over the air, via wifi).
⚠I am taking NO RESPONSIBILITY if you break your phone or damage it.
_ _ _ _ _ _ _ _ _
Here is the fix:
- using an hair drier, you should try to overheat the phone, concentrating the flux of hot air in the back of the phone, just 1cm over the apple logo. I suggest doing this the following way: hold the phone with one hand, using a glove or a cleaning cloth in order to not get burned. To see when the phone is overheated enough, I kept the phone facing a mirror.
- When the phone shows the thermometer logo, STOP heating the phone and let the phone come back to ambient temperature (DON'T put it in a fridge or stuff like that, just leave it and wait).
- turn on the phone, the wifi icon shouldn't be greyed out, and you should connect normally.
_ _ _ _ _ _ _ _ _
I've read (but I don't know since this is not my job) that this works because the wifi antenna overheated while upgrading and somehow the phone feels like the antenna is damaged, so it cuts the antenna out. BUT if you reset the hardware (with the overheating), the phone is forced to check the antenna again and it finds the antenna is ok.
This procedure solved two more problems for me:
- the heating of the phone in certain situations (sometimes in the morning I found the phone heated while it was recharging). After this procedure it never happened anymore.
- the battery lasts longer (it can depend from the fact that you are no longer using the 3g connection, but the battery now can last up to 16 hours)
Hope this helped someone.
I really feel let down by Apple this time, since today (3 years after the problem showed) again I asked for a new phone (since the problem showed up again) and still they asked ME to pay 229€ to have a new one.
Alessio