LossAngeles, no hope :( The problem exists for a long time, but there is no any serious Nvidia activity regarding HDMI audio problems. I think it is better to contact Zotac tech support, maybe they could have an impact on Nvidia.
I have been having the same problem with Aver Revo`s running Openelec version 4.0 based on 319.76 driver but it works with 3.2.4 based on the 304.108
OE4.0 r3610 r3600 Samsung TV HDMI Audio BAD
OE4.0 r3610 r3600 Panasonic TV HDMI Audio OK
OE3.2.4 r3610 r3600 Samsung TV HDMI Audio OK
OE3.2.4 r3610 r3600 Panasonic TV HDMI Audio OK
Thank you for this, you wouldn’t believe how many hours I spent reinstalling different distributions and drivers trying to find out why my audio doesn’t work any more, until I found this thread. Any idea on when the release would be out? Is it also going to be backported for example to the 304.xx series? (that has been working really well for me and wouldn’t want to risk anything)