I have bought a product from china with miniarm 2440 board.
After 6 months its touch had stopped working. I don't have access to internal code.

But TFT is displaying everything fine & code goes step by step exactly as it meant.

So I guess its more of TFT problem. Do anyone have encountered such TFT problems earlier?
Or what could be problem?

 

Well if TFT is fine, then it is not a problem with the TFT. It most likely is a probelm with the touch glass or the touch controller. Does the touch have resistive or capacitive sensing?

 

The screens I've seen use a resistive touch screen that gives you one poke at it (as opposed to say an iPad where you can poke it multiple placed at the same time). Such screens sit on top of the actual TFT and need 4 connections for +X, -X, +Y, -Y. That is probably on a little piece of "flex cable," a long piece of flex PCB with terminations.

See if you can locate that, and make sure it is secure in it's socket. There may be a tab to pull up to get the flex cable in and out of the socket, I have seen that several times.

As a last resort the touch part of the screen is glued over the TFT display, and you may be able to find a replacement, get the old one off, and set down the new one. I say "may" as I tried this once but could not get the old one off cleanly (I broke the display).

Good luck!