Maybe is because of you SDK`s Noise reduction algorithms library has expired(it should pay).To confirm this,please paste the error log when you input “sample-wakeup /etc/avs”.
Sorry , Tom .May be I was wrong just now because the log of sample-wakeup show that the noise reduction algorithms library init OK . And what is the meaning of “but the ‘Tap to talk’ is OK”?It means you can communicate with the Dev Kit and the light is bright?