Others are far more familiar with the V6 (I use a TiVo still), but I'm wondering if your box has had a software update of some kind and/or something's changed in your video output settings.
Home > Help & Settings > Settings > Video/Output - what are they set to? I've read on here that 2160 sometimes doesn't give the greatest result and that letting the V6 upscale to 1080 but the TV beyond that, tends to give good results.
It may also be helpful to other V6 users on here if you post your TV make/model.
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