An idea for solving the firmware problem
 

Why not port Minix to the most common players, those based on the Actions chip. It is a very know architecture well documented on the s1mp3 wiki, there is even an emulator for it. There is some work done for an os called SWAN but I doubt there is much development going on.
So I suggest Minix an os designed for minimalistic embedded systems.( Minix 2 can boot on 4mb of ram and 4 mhz http://www.linuxdevices.com/news/NS5804062141.html )
As MINIX author Andy Tanenbaum says "MINIX is much smaller than Linux and might well be suitable as the operating system for a watch, camera, or transistor radio." So why not an mp4 player?
The BSD licensing will make it very attractive for other companies to use.
Many developers will be attracted to it as long as someone will be willing to do some preliminary work.
I am aware I can't do this but I hope someone will work on this idea.
The Os will mean that the danger of killing players will disappear, no more annoying bugs and unlimited access to the device's resources.
Something similar has been done for the ipod here using linux : http://ipodlinux.org/Main_Page

Re: An idea for solving the firmware problem
 

It's a very good idea, it might work. However even SWAN development stopped because we don't have enough documentation about the hardware on the players. It's pretty hard to learn how things work. However, the S1MP3 project is still alive, i am a registred developer there and the guys don't quite have time lately. I really hope something will be done, but it's gonna take some time.

I think the main problem would lie with the much hardware variation between each player. In the case of brandname players, the hardware is standardised with hardware variations clearly indicated by printed version numbers on the PCB itself. So in this way, an OS could be developed for such players, which would be worthwhile for developers to spend time on the OS as it could be used on all players with the same hardware revision.

However in the case of the mpx players, the hardware variation would mean that the OS would somewhat be required to operate slightly differently between each player.

As alex2pb mentioned, it is this lack of hardware documentation that is hindering the progress of the SWAN project. I guess no one wants to spend time on an OS that could only be used with a selected few players. And it is difficult to identify these "few compatible players" with the large hardware variation going on between manufacturers.

Hopefully someone would be able to develop a universal OS for all players. Just like the Windows OS that could be used on almost all PC hardware platforms.

A solution to the hardware problem would be porting the os to a somewhat brand named devices like Meizu as the players should be as similar as possible. The possibility of having another os would attract people to buy the device and also it would serve as a start point for developers who want to port the os to other devices.
Even one device booting minix would represent quite an attraction to developers and to anyone that likes technology.
And cuz of the bsd license meizu can be convince maybe to give information on the hardware in exchange for an os that they can develop to but aren't forced to release their source code.
The result would be a cheap PDA like device.

If the Linux based Actions 2137 actually happens this should solve most of these problems.

I for one aim to get one as soon as they come out!