Hey guys,

A friend of mine has an iphone 4S, running 6.1.3, suddently his WIFI switch is grayed out, so he cannot turn WIFI on.
I have tried resetting his network settings, it worked for few hours then broke again.

As a last resort i have tried restoring 6.1.3, wifi is still grayed out.
I also tried the refrigerator method, which didn't work, knowing that the "Wifi address" appears in the about section (which probably eliminates hardware errors)

Any idea about that ?

I even asked a hardware shop that i trust, and he said that it can't be repaired probably, but the internet says that the wifi chip can be replaced for 60$

Thank you.
If a software restore didn't fix it, then it's a hardware issue. You'll need someone to help you with it. Where are you located? Maybe I can pass by, take a look at it?