I'm not personally using an X-Finity X1 box, but I do work with them rather frequently since the set top box is very popular. The Slingbox 350 will work with the X1 box, but you will need to invest in an HDMI Splitter (we have an example of one here) as most X1 boxes only have HDMI and Composite outputs and you will need the Component the Splitter will provide in order to stream high definition. You can also use our Supported Video Source Tool to crosscheck specific X1 boxes:
I hope this helps!
Sling Media Technical Support
using the Amazon Firestik SlingPlayer app on my Firestik installed via HDMI to my Vizio TV I get lousy reception and almost inoperable Firestik Remote commands to access/play/rewind my Xfinity X1 DVD via my Slingbox 500.
should I return my Slingbox or would a Roku or chromecast player clear up this problem??
please please help as I'm tearing my hair out with the poor quality of what I thought would be a great experience