You may experience that when you try to listen to HDMI audio from an external source via your device you get no audio or audio noise. This is a known issue, and software has been released for HDMI Audio support in the Xperia Touch.
Note! Software updates are released at different times depending on the operator, market, region or country. Therefore, we cannot give you an exact date for when a specific update will be available for your device. In addition, network operators and specific markets may choose not to use the updates for specific models.