Hi, i bought a mp4 player from mercadolibre, i have tested over 25 firmware files, and some got me to the blank screen, others to the inverted screens and some others to the disabled touch screen.
my problem is solved, this is the from my mp4 player data:
THIS IS THE MOTHERBOARD OF MY MP4 PLAYER 2.8" (Onda vx858LE clone)
htc-039c-rk-v2 2007-11-02 CHEN ,
IT HAS A SAMSUNG 8GB MEMORY CHIP, WITH NO CAMERA
"Mini MP4 Player" startup screen
"Goodbye" shutdown screen
i uploaded this file, a big one, with the firmware that worked for me, the instructions and some other options that could work for you in case that the firmware that worked for me doesn't work for you.
I wrote the instructions in english so that many more people could use the file.