I think this would go here, rather than Playback. If I'm wrong, please let me know.
I just installed RockBox on my Sansa c250, and it works great (after I realized that all the data sent in MTP mode wasn't going to be accessible) except for one thing: When I try to create a bookmark on an MP3, nothing happens. I hit Down, which brings up the contextual menu, go down to bookmarks and hit select, then down to create bookmark and hit select, and I end up back at the WPS. But, if I go to look for the bookmark in either Recent Bookmarks or Context Menu -> Bookmarks, nothing shows up. Am I just doing it wrong, or is there a problem with bookmarks on this model?