Can't hear sound on the videos

[benjee_uk]

i have this mp4 player Solar-Powered Nintendo-Emulating MP4 Player (Go China!) - Boing Boing Gadgets.
i suspect the firmwhare to be faulty. i can't hear the sound on the videos can some one help me flash it with new firmwhare?

[Binh@MyMPx]

Does the sound work while you listen to music or radio?
Do you have a sample video that came with your player? If so, does that play sound properly?
It may just be the way you are converting your videos that no sound is coming out rather than fault with the player.

But if you can answer the questions above, that will help.