I've had my Sena 20S for about 2 months now, and I've been loving it except for a couple small issues. About 2 weeks ago I upgraded the firmware to 1.7.5 (from 1.7.1 or 1.7.2). Now fairly frequently I will use the voice prompts to start FM radio or Stereo Music, the voice will indicate I have tuned my radio station then nothing.... I can change stations, the voice prompt tells me I have changed stations and there is no sound.
The same when I tune Stereo Music, it says I have tuned stereo music then no sound.
Turning up and down the volume makes no difference.
The only fix is to turn the headset on and off. After 2 or 3 times I can generally get it to start working, but it is a huge pain while you are commuting in traffic to have to keep giving commands.
For now I have downgraded to 1.7.1 (as of today.. haven't tested it to make sure it doesn't happen again). 1.7.2 only showed that it added mulilanguage support and I don't need that.
BTW - my only other problem with the 20s is that while the music cranks up when it's noisy, the voice prompts seem to stay quiet. I have to memorize what the voice prompts should be and try to give the right command at the right time because I haven't memorized all the the wheel commands yet, and it doesnt help if you're trying to reset your device while driving 75 mph and aren't sure if it is on or off because you can't hear what the voice is saying.