UPDATE: a few software upgrades ago all my sound came back after being dead for two and a half months. There were several software updates between when it died and when it started working. I guess it still could be a failing amp but I feel it had something to so with the software upgrades.
It...
I started experiencing the exact same thing about three weeks ago. Unfortunately the nearest service center is a two hour drive... so I drive in silence for now. If anyone has a fix please post.