Many new users of this board get carried away with the possibility of upgrading theor firmware, only to find out moments later, that they have bricked their device and that it won't turn on again.
It is amazing, as well, how many people place a post asking about their own specific device and corresponding firmware.
To those people, my words of advice:
1) There are hundreds of different MP4 player models out there! These devices share some common components and the firmware is modular. Any company in the world that wishes to sell mp3-Player can easily cook their own player from these components and have their specific firmware made.
2) Even if the player looks similar to another one, that does not mean, it will run with the other's firmware!
3) Not all iPod Nano clones are firmware compatible between them!
4) You have to read the forum, the website, the wiki and the FAQ, to find out more about your device, before asking!
5) If your player works fine, don't mess with the firmware upgrade. Chances are, you will break the device!
6) If you open your device, or flash it with another firmware, you loose warranty.
7) The most comon problem with bad flashes, is that the device will neither turn on, nor be recognized as an USB device, so you cannot flash it anymore. This is because the device hangs before it turns on the screen/menu. Since the player does not detect a bad flash, it won't turn on in a special mode, that still alows the firmware flashing. This mode can be invoked by physically shortening a few pins on the flash-chip. Even then, you need to find a working firmware and a dumped one will not do, as you need a complete firmware. All of this is explained in the wiki.
If you are going to mess with your player, BACKUP YOUR FIRMWARE FIRST!!! Read the wiki/FAQ on how to do that.
9) Modding the logos and animations is quite save. Modding with files or hexeditor will probably brick your player.
Reasons for upgrading the firmware:
1) You have found an annoying bug which is solved in a newer (or older) firmware.
2) Your player only supports MTV files (no compression) and you prefer AMV playback (with compression - 2h movie gets as small as 200MB).
3) There are some utils or games in another firmware release you prefer. Make sure that the firmware is compatible first!
4) You like to have your own custom logo's and animations, because you are a nerd!
I hope this helps in preventing so many posts that start with: "What is this player..." and end with. "Help! My player won't turn on afte upgrading...".