I found a working firmware for the Rockchip RK2608C here:
» Firmware, Manual, MP4 Tool and AVI Converter Smart II
At the buttom of the page there is this link:
http://www.oem-drivers.com/wp-conten...ct%20tools.rar
This zipped file contains a firmware file called "firmware.rfw". The included flash program is called "Product Tool No Dog 3.2.0.5" (Consumer.exe).
It revived my MP4 player, good luck to you!!