Technically, but the devices they support are fairly limited and as far as I know Rockbox hasn't been updated for something new in years.
Shows how often I use my mp3 player. Phones play flac though mine does
Just because something is portable does not mean you have to use it on the go. I would love a portable FLAC player with line out because I could plug it into my office stereo, then my living room stereo, then the car. Nevertheless, it's a pyramid tube of music with a crappy looking UI. I can make do with my iPod Classic and my VBR 0 rips for a long time.
Valid point. I suppose the real issue is I don't understand wanting to use FLAC outside of a few sets of circumstances (archival, etc). V0 or 320 seem like better options regarding the file size to sound quality compromise, will sound pretty much the same as FLAC on most people's headphones/stereos, and they work on basically everything.