I have recently updated my iphone 4's OS from 5.0.1 to 6.1 now I'm not able to use wifi option on my device the wifi button in setting is grayed.
even i have been facing wifi greying issue on my 4s since November 2012. wifi toggle was greyed out and nothing fixed it. occassionally once in december my wifi somehow was back as i had put it in airplane mode and switched it off for 12 hrs or so. but it was temporary for 4-5 days the problem continued until yesterday. i read a post where a guy had put his fone in the freezer for 10 min and his wifi was back. sounds crazy but being frustated of this issue i tried it out. i switched off my fone put it in the freezer for 10min and wifi was back. even i hadnt believed the guy who had first written this procedure. but it has worked for some including me. try it out at u r own risk
This is NOT a good idea. As you have indicated, the switch to Airplane mode and then back out fixed your problem for 4 or 5 days. What makes you think that your "freezer fix" is not going to do the same thing once 4 or 5 days have passed.
I know you indicated to do it at your own risk, but even posting this solution is a bad idea....
I tried every possible thing on this planet to fix the problem but all in vain. I knew abt the freezer thing since last November but I never tried coz I knew it wasn't a good idea but I Finally tried it out as I was so sick of this problem and it worked and it has worked for many ppl around the world. Many ppl also suggest that u can heat u r fone using a hair dryer for 1min just below the lens of the camera. Well I din try that but the freezer one worked for me. Rest I tried updating-restoring-reset-setup as new device-downgrading which I later came to know is not supported for iPhones.
Btw there is no other option than the freezer method, the hair dryer method or apple store replacement method in which most of the people either have crossed their warranty period or have purchased from another country and apple is not gonna listen to us coz if they wud have they wud have fixed it in 6.0.1 or 6.1 even after so many users complaining abt it. So u either wait for iOS 7 or u live long enough to see yourself getting frustrated coz of this issue