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H92S - Lost AC3 downmix after ATV6.2 software update


Hi All

Strange issue here with my new Zgemma H92S. Its been running ATV6.2 build 2019-02-26 with Whooshbuild for a few weeks with no problems. I have AC3 and DTS downmix enabled as my box connects directly to my TV via HDMI with no AV receiver inbetween. Yesterday I decided to check for software updates as there were over 100 pending - this completed successfully, but since the box restarted my TV now says there is unsupported audio being sent to it. I've checked the Zgemma and the audio settings have not changed, AC3 and DTS downmix still selected. Any channels with AC3 audio are muted, if I switch to MPEG then audio plays fine. I figured an update had broken an audio driver or something so flashed to the newest ATV build 2019-03-09 but still the problem is there. So I then down-flashed back to the original ATV 6.2 2019-02-26 build that the box was running before the updates but oddly the problem is still happening... I've tried a different HDMI port, no change.

I have an old Zgemma H2S running ATV 6.2 2019-02-17 and when I swapped this in to test it works fine with no problem on AC3 audio channels, so the issue is defo with the H92S box.

Is it possible the software updates changed audio firmware on the H29S that now can't be fixed by going back to an older working ATV 6.2 build?

Does anyone have any suggestions as to how to proceed and get the H92S working properly again? I'm guessing I've missed something but can't think what...?

Any help gratefully received from you clever chaps!



Forum Supporter
maybe a fresh flash and leave plugins behind as box has low ram as i am having problems also with this box ,,this might leave problem behind you on new flash ,,, also have you maneged to get a backflash to work on other box or to reflash your own box from earlier flash ?also format usb every time on pc as well as box a double flash as i often do helps clear out old set ups
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TK Veteran
Forum Supporter
Best to reflash rather than doing updates as updates can cause issues and I always setup fresh rather than restoring settings from an old image.