This is an old post but I found myself looking for this answer. I went through the symptoms of not hearing anything, then only hearing but the mic didn't work, the phone button was not recognized by my phone. But as all this was happening I did look on my phone blue tooth area and I did have my Sena SMH5 paired and the media audio and call audio check marks checked.
This is what fixed my head set. I updated the firmware on my SMH5 to 2.2.3. Then reset the SMH5 to factory and Unpaired my phone. After that I rebooted both phone and SMH5. Now after pairing them together I still did not get all the functions. But out of frustration I did not un-pair them I actually selected the pair function on my SMH5 and by itself my phone repaired them together again. By my surprise I have the media audio working but the the phone audio / mic. Ok I set my SMH5 to pair again! and my phone paired again! In my phone I now see the check marks again next to the Media audio and phone audio words in bold. So now I press my phone button on my SMH5 and my phone asks me what do I want to run when I do this, such as Google, Assistant, and what ever else by voice assistant the phone has. So I selected Google. Now phone when I press the phone button on my SMH5 opens up google assistant and I can say any command Google offers. Such as calling, gps, and well what ever google assistant does. So finally I can call, gps, save notes, make a grocery list, listen to music, movies, and what ever. Bottom line my mic and speakers work perfectly and completely controls my phone by voice control.
I hope this helps anyone now days who happen to find this post.
Good luck.