@rajendra:
1) In an earlier post (here's the link in case you missed it), admin mbolivar reminded users to either a) search for a topic which matches their comment or b) start a new topic. Hijacking threads is not helpful.
2) In response to an earlier comment you posted (which was very similar), user feurig suggested a link to the LeafLabs documentation. It is not clear if you found the bootloader.html page helpful. If not, what did you do? Your specific comments will help improve the page.
3) Please remember that the board you are using is not produced by LeafLabs, but is a "clone" of one of the LeafLabs boards. Have you tried to contact the manufacturer of your board?
4) It would help other users solve your problems and answer your questions if you describe more details (which I admit is not easy if you are using a smartphone). For more posting guidelines please read the very short LeafLabs "Guidelines for Posting" (a "sticky" topic at the beginning of the forums).
Good luck.