:lol: hope this helps some people ,here you will find firmwares for
ATJ 2135 = action 2135
ATJ 7515 = ACU 7515 / ATJ 2097 / ATJ 2091 mp3 AND ATJ 2091 mp4
http://www.sungworld.com/en/software_en.asp
here is the products page
http://www.sungworld.com/en/products_mp4-atj2091.asp
open the actions tab on the left and look for your player on there list
take a note of there product number,and download the appropriate firmware from the top link