invalid sim card error - solution

I was having a long time random errors - invalid card please restart and so on, especially when it is more worm outside. I was reading that some people put some thin metal stuffs on the back of the phone etc. . But that stuffs are not helping and they are not very useful with that amount of plastic between chips and back site. Before some months my warranty already expired and as it was not fixed by repair service I open phone by my self. There are 2 chips that are cooled by the screen on the front through pink thermal pads - memory chip and maybe the other is some driver for gsm part - I never search what was exactly. The more interesting stuff is that there was no sign of chips on the thermal pads. I put some thermal compound on the thermal pads and after that for several months I am not facing that error any more(in the matter of fact only one software bug with sensor buttons, that resolved with restart for 4 months, no other errors). By my opinion is is a defect size of thermal pads on the 9505 phone(or may be it is designed defective :D ). Most probably the best solution is new thermal pads with proper thickness, as the thermal compound loose it's performance in time, but thermal compound is easier. I hope this will be helpful for the others, who have same problem.