I also have an issue with my w4400nex. I followed the guide here and got a new SD card flashed and installed. It seems to work well (it boots), but once its booted it will not play music the radio tuner does not detect any stations.
I can see that its playing music via bluetooth but hear no sound. I can hear menu clicks and google assistant works, but music will not play.
Img file used: https://mega.nz/file/SdJCgKCJ#13zrFlogMCWNohCvuFsDFcC1uniHgufVZJxZlQPHUag
Any suggestions?