HI,

the first thing to remember is that the Empeg is a piece of custom hardware, which has a custom version of linux that runs on it and includes custom written drivers for may of its components (DSP, screen etc).

While it is possible that "some other ARM OS" may boot on the Empeg, it is hard to see what advantage that would be as the chances are none of the features of the Empeg would work without significant hacking to the "other OS" and unless this other OS was able to read EXT2 disks then you wouldn't even be able to do anything sensible with the hard disk.

I would think that unless you are pretty familiar with both the Linux kernal and this other OS then this is probably something that you probably don't want to "just try to see what happens" as you would not be sure if any physical damage could occur that may make your Empeg unusable.