Hi Kalal. I have worked on FLASH application on several projects but I haven't faced an issue similar to yours. If i were to guess, after you write data to FLASH, you may not have locked the sector. This means that if there is a system reset, all available address default to zero. If the Flash is unlocked, then it will also get overwritten.

If this is not the issue, then I would suggest you trace you code in the debugger using break points. That can really help in knowing what the issue might be.

Good Luck.