This evening, I started my device and it was 1080p50hz... (i switched again to 2160p60Hz) and the Video Color Space was YcbCr420...8 bits. Won't switch to 420 10 bits saying "selected is not support"....

.... and 444 8 bits no available too !

....and after playing demo (Sony_4K_HDR_Camp) or movie, the player goes back to 1080p50Hz !!

PS: HDR Switch still works on his side
PS2: I just tried all Video Color Space settings, NO ONE is "supported" for now !