WIFI greyed out, looking for an effective, long terme FIX

Hi i see that there has been numerous iPhone 4S out there with wifi beeing greyed out and problems with bluetooth. It seems that the probleme is IOS7 thinking the WiFi chip/Antenna is overheating and shuts it down. There's has been way's to fix this such as the freezer or the blowdryer but these techniques only seem to be a temporary fix as the issue comes up again several, hours, days later. So I am wondering if there is an effective fix to this such as changing the upper wifi/jack antenna to a new one ? I see it's also possible to get brand new Wifi IC chips for 15$ but then it needs to be soldered to the board and needs professional assistance... I am wondering because on it's latest iPhone 4S it seems Apple has corrected this issue since the wifi greyed out seems only to be affecting the older iPhone 4S. Any suggestions are welcomed ! I have two iPhone 4S one with a WiFi issue and the other one doesn't so I guess there is a solution just have to find it !