Comcast/Xfinity X1: No signal hdmi

I have the X1 Comcast DVR box too. Trying to set it up with XBOX ONE. The HDMI Out from the comcast box is going into the HDMI IN for XBOX ONE. I see no signal. Comcast confirms me that they are able to ping the box and signal is fine. Am I missing a setting
that I have to do in XBOX ONE to make it working? Asking for help?

Set up Comcast box manually. Type in Xfinity instead and see that gives you more choices. I have a x1 box from Comcast, could not find it until I typed Xfinity.

Hi Swanlee,

Try setting make=Comcast (or xfinity), model=X1. That should work.

Curious to hear if the SithLordBlack was successful. Bought a SSIG 1x2 HDMI Ampified Splitter and both TV and Xbox One could not get signal. Checked HDMI cables and they all work if Xfinity X1 device is hooked directly to Xbox One but didn't work through
splitter. In fact, couldn't even get signal on TV so neither split worked. Spent $90 on it at MicroCenter so it's going back. Saw a Rocketfish Splitter at Best Buy I may try next. Please let me know if you have had success splitting the signal. Trying
to split Comcast signal so wifey can watch TV normally through AVR or I can watch football though Xbox One with the NFL App.

I am having the same trouble using the standard X1 box. During setup - I've tried selecting Comcast or Xfinity (no Comcast X1 option available) and the Channel up / Down features don't work. I can continue forth however when watching TV I can't use the
pause / ffwd functions, nor can I select a channel to watch from the OneGuide. Any Ideas? My Kinect is sitting on top of the cable box...not sure if this contributes to that issue?

Sony Monolith TV: X1-->HDMI (from xbox box) -->XBOXIN. XBOXOUT-->HDMI-->TV