What a strange world this is. Since I have gotten this unit last May, I have Red Button, Pulled the Plug & Rebooted from the Tools, and still no 4K. BUT from your suggestion I did a RBR and there they are. BUT, again, you have to wait for the box and TV to "talk" or they are HD. I went back to check again and the TV didn't go black and come back and they were HD, then the flash and UHD. Looks like a tad of a Handshake issue . . . I had something like this with my 2008 DLP when 1080i/p came out. The DISH box took its time acknowledging that the TV was capable. Also, I only get UHD and no HDR. Yet, since the WC was in it.
Thanks for the nudge. I would have thought, "Not yet", maybe with U518 . . .