Hello, this is an FYI that there seems to be some bug and I'm not sure if its' the LG implementation or Fios TV Mini one box. I've tried 2 different HDMI cables that support 4K. Basically, if HDR is on the LG screen flashes every few seconds, if I turn off HDR on the TV one mine all is fine. Also on my TV if I enable HDR I see a "Dolby Vision" box pop's up so the handshake I guess in some way is working initially to sync up. Now there is no HDR content that I'm aware of on FIOS unless I were to watch some HDR content using the youtube APP on the Fios box. I can get around this by launching the youtube app from the TV itself and not the Fios box, but I have read in another forum another person with the same issue. Looking to see if anyone has had an success enabling HDR on the Fios TV one mini box . Not a big deal at this point and hopefully some later firmware will solve this either from FIOS or LG as I don't know who the culprit it.
There was a bug reported with the mini where HDR was always enabled regardless of source. Supposedly that was fixed with the latest firmware update. You should check to see if yous is up to date.