Hi All,
I have had this greyed problem for months now, nothing seemed to work by fiddling with settings, resets, restores, etc. I never tried the freezer thing, I used to blow hot air from the hair drier for 3-4 minutes while the phone was switched off.
Did it 2 times, switched back on after letting it to cool down, button was not greyed, found wireless network but could not connect...
Today it was hot, decided while sitting outside to let the phone on a clear sunny spot to get fried and shutdown.
Indeed after 20 minutes the phone had shut down due to overheating (it was real hot could barely touch it), letting it cool down, checked button was still greyed. I then did a soft reset (power & round button pressed together), switched phone back on and wifi button was not greyed and I actually could connect and now using the wifi.
I don't know how long it will last,but if I have to do it once a day it will save me the 120euro the have offered me to replace the wifi chipset (they say it's the chipset problem). In any case I will also try again the blow dryer but with phone ON so that it shuts down by itself.
hope this helps
Alex