hi all
I have been pursuing this issue for quite a while now. I won't go into the "Apple as a company" discussion as it appears from this thread and many others that they have not reacted for the past >6 months to thousands of complaints on this issue and probably will never do as they have already moved on with new iOS and new iPhone models. I hope I can add to the TECHNICAL discussion by summarizing my experiences and especially I hope I can save you time.
1. In 2012 I purchased a brand new iPhone 4s and 5 months later I upgraded from IOS 5 to IOS 6 over the wireless (note: this is important - not via the iTunes MacBook)
2. immediately after Wifi and bluetooth greyed out - tried all imaginable software solutions - zero result
you are thinking: so far nothing new...
3. then I took my iphone back for repair - they replaced the wifi/bluetooth antenna - zero result !
4. then I took my iphone back again for repair - they replaced the connector between wireless/BT chip and antenna - zero result !
5. then I took it back a last time - the reseller/repair shop was also out of ideas and they decided to take it apart and to heat up the wireless/BT chip up as they thought the issue was with the soldering of the chip on that board - they have had hundreds of iPhones brought in with the same greyed out issue - the result was the wireless was now working and has done so for at least 6 months - then died again
6. they now can not help me any more and also I have evidently lost my warranty as I took it to a reseller/repair and did not send it back to Apple in the first place.
7. This happens also in Iphone 5 and with IOS 6, 7 upgrades all over the globe. But most reports are with iPhone 4s.
To sum up:
1. it is a hardware issue - namely the connection of the chip to the motherboard;
2. it will happen in iPhones (or iPads) which are at the edge of technical specifications and overheat if you download for a long time or do a large software update (like an IOS upgrade);
3. it will most likely happen when you upgrade your iPhone via your wireless connection (long download - more overheating) instead of through MacBook - iTunes -USB;
4. depending on the continent/country you live in you might get 1 year/2 year warranty - don't let them fool you and send you home trying to do all sort of software tricks and router resets or whatever - claim your warranty immediately !! I have read threads of people even buying new home routers aso. Be assertive !
5. whoever reading this: stop losing time on it. I have spent hours and even days figuring this out, driving back-and-forth do the shop aso. You can not solve it unless you are a micro-electronics engineer with a work place. You may temporarily fix it with temperture modulation (hair dryer, freezer, whatever) but that is only a patch which will frustrate you eventually. I even read messages of people hair blowing it every two weeks...come'on...
For the past 10 years all my personal and work equipment I bought from Apple and I still think their smartphones, tablets, laptops,... are the best and most user friendly. I did not go back to microsoft solutions and I even went on to buy an iPhone 5 which I upgraded to IOS 7 last week using my Macbook and iTunes through USB.
That being said I am extermely disappointed in this issue, in the complete lack of repsonse of the company and in myself for being so naive and trying so many things losing so much precious time. I read a very wise comment by another Apple Support follower who wrote: if this would be the car industry - companies like Toyota would be forced to take back 100.000's of cars for repair all over the world.