Original sentence: Compatibility with free software operating systems such as Linux is not officially supported.Some hackers have published hacks or workarounds that allow owners of iPods to use the audio player and operating system software of their choice.Those who use third party MP3 players with their iPod or free operating systems such as Linux claim many countries have legal restrictions which could prevent reverse engineering for compatibility
Edited sentence: Some hackers have published hacks that allows those people to use iTunes, but all of them have been quickly disabled by Apple who is keen at keeping the illegal uses away.Those who use third party MP3 player instead of iPod or minor operating systems such as Linux have complained that the lack of compatibility effectively limits their freedom to use systems that are not officially supported