All I want to do is to add some my own features to my portable MP3 player (iAudio 9). So I am wondering is that possible to reverse its firmware(The latest firmware: http://www.cowonglobal.com/download/Firmware/iaudio9/iAUDIO9_1.11.zip)?

And all I know is its chip might be(just might be) telechip(http://www.telechips.com/).

I knew some high-level programming such C/C++, but know little about doing this?

Any one could help?

I think you could start by identifying the hardware present in your player.

Here there are specifications:
http://www.telechips.com/product/p_028.asp
http://www.telechips.com/product/p_02_2.asp
http://www.telechips.com/product/p_02_3.asp
http://www.telechips.com/product/p_023.asp
http://www.telechips.com/product/p_024.asp

You need to know more than C++ to reverse engineer things. You have to be familiar with the device's CPU and its assembly.

But most likely the firmware will be cryptographically signed anyway, meaning that your MP3 player will only accept original, unmodified iAudio firmwares. Even graphical calculators (e.g. from TI) have signed firmwares. You might manage to reverse engineer and extend a firmware, but the player would then simply reject it.

I've worked on a couple of MP3 players in my professional career, and what arc says is exactly right! The updates were signed to prevent unwanted modifications which would cause tech support calls, and a general nightmare.

Guys, believe it or not, the firmware ISN'T encrypted!

In that zip, it's the (imagine this) *_FW file.

The chip in the unit is the TCC79X. As there are comments about the drivers in the image.

"TELECHIPS TCC79X USB SYSTEM"
"x6 SIGBYAHONG_NANDIO_TCC79X_V005364"

It COULD be running the Nucleus OS, as the fat implementation that they use contains the same error messages mentioned here: http://read.pudn.com/downloads36/sourcecode/os/112975/file/PCDISK.H__.htm

Uses the FAT file system.

Supports MS MTP. (Which is a nightmare!)

Has a SWF player in it.

And appears to be written in C, not C++.

Other than that, I can't really tell you much about it. ;-)

Check RockBox project. It supports Telechips and source is free.

for further (very valuable) info check this url RockBox TelechipsInfo ("http://www.rockbox.org/wiki/TelechipsInfo")


Uhm and yes they have firmware structure info and this chip is an ARM.

Good Luck