WIFI option has been greyed out

Update to latest OS (.2). It will fix it.

I have same problem I havent used wifi for 2 weeks. I tried to do everything to fix it but I couldnt. it seems that it is nothing without wi-fi disappointment

This update (.2) is only for new devices (iphone 5, mini ipad). There is NO fix from apple for older models, like mine, iphone 4s !!!

After upgrade from 5.1.1 to 6.0.1, wifi greyed out.

Modular is wrong (probably works for Apple) - it is a software problem they can fix for the 4s but it can only be done in an Apple Store. While I would never rule out the possibility of an equipment failure on a given phone, there are literally thousands of complaints about the loss of wifi service after the new OS came out. There's just no chance all of these issues are equipment problems. GO to the Apple Store and demand that they update your 4s to the new OS update .2 It will fix it - it fixed ours.

Your understanding of this is just as ignorant as your claim that I work for Apple... The grayed out WIFi has been reported just as frequently after EVERY update since 2.0.1 (possibly earlier). It can be an error updating the iOS, but frequently is hardware failure during firmware burning part the update.

Maybe if you spent more time researching this issue, and even reading Apple's support article about this - instead of boollsheeting about a double secret probationary Apple fix, you just miight become remotely useful.

FYI there is no 6.0.2 update for the 4S, only the 5. (If there were, it would have been made available for everyone.) If yours was fixed by restoring the iOS, it's something you could have done at home.

Just to add my 2p worth.

I turned the light on the phone on and kept doing video recording to drain the battery, I let it die completely, recharged it and the wireless came back on. Powering on and off through the software and power on buttons didn't work. None of the other suggestions I'd read were any help, and to be honest some were stupid. Your method of draining the battery is up to you, the light and video is a good way to drain it quickly.

In my case this was not to do with upgrading IOS, I last did this weeks ago when it came out, I haven't got the phone wet, it was working when i left this morning and didn't work on myt return back home this afternoon.

The best thing I can think of is that there is some hardware on the wifi that gets put in an inconsistent state through something (no idea what) and that powering on and off does not fix it as there could be some sort of trickle going through the hardware to keep it alive. Draining the battery allows the hardware to be really turned off and it puts it back into the right state.

I did not do a factory reset, though I unsuccessfully tried the following:

Turning it on and off.

Turning the Airplane mode on and off, leaving it off for five to ten minutes.

Turning on and off 3G.

Turning Siri on and off. No idea why, somebody said it worked but I doubt it myself.

I checked each of the options as much as I could in the Settings App, but nothing seemed odd.

Reset network settings. Did that a couple of times and nothing changed.

Things I didn't do:

Heat it with a hair dryer. Mad idea #1

Freeze it in the freexer. Mad idea #2

Reload back to a known restore point.This was the next step.

Reset it back to factory settings. This was my last option and it was just a pain to do but its time consuming more than anything else.

Of course your milage may vary, but draining the battery is a simple option to try and costs nothing.