Picture of Rockbox software for ipod image
Rockbox is an open source replacement firmware for mp3 players. Rockbox runs on a wide variety of media players now: iPods, iRivers, Archoses, Sansas, Cowon iAudios, and Toshiba GigaBeats.

It runs on a number of different models:
- Archos: Jukebox 5000, 6000, Studio, Recorder, FM Recorder, Recorder V2 and Ondio
- iriver: H100, H300 and H10 series
- Apple: iPod 4th gen (grayscale and color), 5th/5.5th gen video, 1st gen Nano and Mini 1st/2nd gen (Nano 2nd gen is not supported)
- Cowon: iAudio X5 (including X5V and X5L), M5 (including M5L)
- Toshiba: Gigabeat X and F series (the S model is not supported)
- SanDisk: Sansa E200 series (the R models are not supported)
- Additional models are in development

With iPod, installing Rockbox involved copying a hidden folder containing the Rockbox program itself to the iPod, and then running a Linux app (Mac and Windows versions are available too) to patch the iPod’s bootloader so that it will look for the Rockbox program, rather than Apple’s OS, on the hard drive.