I was also using 54 brightness prior to this most recent firmware update. What value are you using now for brightness?
My initial impression after update is TV is darker and I would like to revert back to previous firmware if possible
Was it so that one also needs to set the ATV source in TV as PC or something to make the 4:4:4 to work? Or am I wrong on this?I have my ATV4k set to 4k SDR @60Hz, chroma 4:4:4 using YCbCr, with Dolby Vision enabled. Chroma 4:4:4 is part of the HDMI 2.0b hardware specifications, of which the ATV4k and the C8 are both capable. Audio format is Auto, with Atmos enabled. My cable runs are short so I use Premium High Speed HDMI cables and they pass the internal HDMI cable connection checks with the ATV4k with no issues at all. I have the C8 do all of the upscaling, whether the video is coming from the ATV4k or the UBK90 (UHD/Blu-ray player). PQ is gorgeous with any source and the audio is perfect.