IDK whether this makes sense, so see it as a wild guess: I ran once into similar situation (but was different). Out of the sudden I could could not get fmtx to transfer to my car. Cannot remember if bandwidth was japanese (down to 76) but for sure I could change frequency. But that did not help. Neither did a reboot. So I did a full power cycle (shut down, pull battery, push power button for more than 3 seconds, reinsert battery, power up). After that it worked. Worth a try?