Does rockbox work alongside the Apple firmware or completely replace it? Support for Photos yet?
Yes and no.
Both firmwares will be usable, but the trouble is the way Apple and Rockbox browse music. Apple has their own DB, and the music is dispersed through files in random directorys. Rockbox, on the other hand, is directory based.
For example,
Rockbox: K:\Music\Coldplay\Parachutes\03 Spies.mp3
Deafult firmware: K:\iPod_Control\Music\F30\JKZL.mp3
Since Rockbox doesn't yet read the deafult firmware DB, the only way to listen to your music from the deafult firmware is completely random. (As you can see, the directory and file structure above doesn't tell you anything.)
The upside is, Rockbox supports drag and drop. Just drag and drop the music onto the iPod drive, and you can play it. However, this same music WONT be accessible from the deafult firmware.
Eventually, someone will probably program something that'll read the iPod database and let you use both seamlessly, but since thats not out yet.. the only option is to have the music on your iPod twice. Or at least, any music you want to listen too from rockbox.
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As for the original question,
Yes - I'm using Rockbox on my iPod. The picture viewing is superb, game plugins really nice, and gapless playback and EQ features are great. I recently released my first theme, too.
I have not, however, switched all my music over to the rockbox drag&drop. One, I can't submit tracks played in rockbox to last.fm, two it doesn't display lyrics (or album art, but that is coming really soon. Already a working patch for it.), three no iTunes sync. Any time I update the id3 tags, I'd have to manually update it.
I'd REALLY like an ipod db paser.. so I can use iTunes to manage the music, and access it all from rockbox.
Josh