Hallo Rahgunathan,

I didn't laugh, because I probably didn't understand your posting.
Do you fear that code becomes wrong and mcu fails doing it's job?

Well, in Flash memory logical levels are represented by a very small electric charge sitting on a highly insulated gate of a FET: Charge sitting on gate is extremely small and was put on it by tunneling process (quantum mechanics).
That this reliable works is a fact, but for me it still seems to be a miracle.
This extremely small charge is very vulnerable. So, it can erroneously removed by heat and nuclear radiation. Fortunately, at room temperature and normal environment reliability of Flash memory is very, very high. But when environment is changed, this has to be kept in mind.
Some weeks ago a had a look at datsheet of ST62C20 and found to my surprise a very detailed diagram about data retention time versus ambient temperature. Data retention time is the time it takes for a big amount of devices that a certain (to be defined) percentage of devices undergo a failure.
From diagram it could be seen that at 20°C room temperature data retention time is 100years. But for 55°C only 10years can be expected. And for 70°...80°C data retention time is only 1year, which seems to be a terrible short time!

Other circuitry in mcu should not undergo any change, because circuitry works staticly. Means, a flip-flop which is one time set, will not undergo a change by heat or something else. Extreme conditions excluded.

Bye,
Kai