We talk for 4:2:2 10 bit, not only for 4:2:0 10bit where work on 4K STB.
It should be work, but not work. We talk for really work 4:2:2 but for now not see me to work, we wait proof STB DM 900 no only someone posted fake info for turkey forum and boom dm 900 work with 4:2:2.
Not fake. Continue to experiment with your DM900.
More importantly ! All 4k receivers can decode 4;2;2.
"4K chipsets" is able to handle 4;2;2 video density. It can also work very comfortably.
Of course, certain conditions must be satisfied also.
As long as, Processor's "root software" should support.
So, the real question to be asked here is; Is there talent or not? Yes there is.
Because, 4k processors are very powerful for 4;2;2
Mpeg2 & 4;2;2( 576i )
Mpeg4 & 4;2;2( 720p, 1080i/p )