“iriver […] decided to only release Microsoft’s proprietary Media Transport Protocol (MTP) versions of their new T series MP3 players to Europe and the US, thus locking users into using Windows Media Player 10 and Windows XP to transfer music to their players.
iriver had a good reputation for listening to their customers and now maintains UMS firmwares for their older iFP line of MP3 players as well as firmwares for their own original proprietary transfer protocol. Luckily for us, they did release UMS versions to the rest of the world and so the firmwares were out there ready to be tried. Under normal circumstances an MTP player will not accept a UMS firmware, but we managed it! The conversion process is as simple as upgrading a player normally.”
mtp-ums.net via charles
some links added