hello bolkebear59,
I am surprised that you have problems of image and sound with vidon, 
just for to be sure, as you choose ''vidon hdmi'' in the options ''passthrough output device''

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you can follow this procedure, often it solves the problems
Egreat A10/A11 The instruction to force to recovery the firmwarehttp://en.egreatworld.com/comunity/index.php?threads/egreat-a10-a11-the-instruction-to-force-to-recovery-the-firmware.396/
see you