Yesterday I got a iRiver H10 in return for helping out with a virus infected computer. So the first thing I did was putting rockbox on it. Next step was to make it work with my Ubuntu where I use Rhythmbox. The Rockbox installation was rather easy though it has some glitches.
Connect your iRiver via USB and check if it shows up as USB mass storage device and gets mounted. If so it's a UMS if not it's a MTP player. Don't ask me what these TLAs stand for I just know that you have to choose the right type in the next step. I got a UMS one. For MTP ones you need to use a trick: Remove the battery, put it back in, press and hold the "o" button and then press the power button. It will start up in USB mass storage device. Remember this trick for later.
The automatic detection did not work for me so I had to choose my model H10 (5 / 6GB) UMS and my mountpoint /media/H10 by hand.
Use complete install to find out you might run into permission problems. Then do a sudo chmod -R u+w <your mountpoint>/System/ to fix this. Now run the complete install again.
When your Rockbox fires up for the first time after installtion it's a nice feeling, but the moment hook it up via USB to your computer to upload some files you might get a little shock. USB doesn't work under Rockbox, yet. But no worries, remember the trick from step 1? With Rockbox the player switches off completely so you don't need to take the battery out. Just press and hold "o" while switching the player on and it fires up as a USB mass storage drive. You have to do this whenever you want to connect the player to your computer until the bug is fixed.
The next problem was to get Rhythmbox to work properly with the player. The problem is that the path for the files to store is not recognised properly by Rhythmbox. This can easily be fixed by creating a file in the root of the player