It looks like the people behind the
Rockbox* MP3 player firmware/OS (which runs on Archos Jukebox series hardware) have started preliminary work on porting it to iRiver devices; they're starting on the (discontinued?) iHP-1x0 series, but hopefully that'll lead to an H-3x0 version as well (assuming that they're based on a similar architecture).
* not to be confused with Rocbox, a MP3 player brought out by rap record/fashion label Roc-A-Fella. (Hang on, aren't they part of Def Jam/Universal? If so, I wonder if their corporate parent knows that they're putting out a MP3 player.)