If the HD HERO2 camera is not recording any audio, it could be a one-time glitch being caused by a bad connection in the microphone port on the camera. Please try the following:

  1. Remove the battery from the camera.
  2. Insert and remove the microphone jack from the microphone port on the camera.
  3. Reinsert the battery into the camera.
  4. Power on the camera once more.