Hi Mike,
In order to make sure there is audio stream available in the TV, we bought a Pioneer AV receiver with ARC function. It turns out the ARC of TV is fine.
So in terms of ARC, why the TV replied to ADV7511 with <Feature Abort - "Cannot provide source">, while works fine with Pioneer AV receiver?
My guess is maybe there is something else we need to do before sending the <Initiate ARC> to TV.
By the way, is your ARC working after you sent the <Initiate ARC>?
Regards,
Phil