Depends which service was previously tuned before tuning to a 4:2:2 service. Sometime black, othertimes the Mio 4K has enough valid data that it attempts to apply correction and display.
Streaming from the STB to another device on your network has nothing to do with Internet speed. Your router shares the connection between the STB and the playback device on your local network. No Internet connection is used or needed to stream the STB channels to another device on your network.
I knew there was something I wasn't understanding. I have a good network with all new equipment. Had to replace it after lightning took it out. I just installed a 4TB network drive the other day. Right now, I don't have my STB ran through it, but that's no big deal. I have everything else in the house hooked to it. I'll play with it and see how it goes. Thanks for the info.