How are you using PVR/Live TV functions in XBMC? What is your live TV backend Server?
I am currently using spmc "gotham" on my amazon fire tv for PVR/Live Tv. I have a Kworld usb tuner connected to a windows 7 desktop using windows media center as the backend software. I use the windows media center PVR on this SPMC "gotham" which utilizes serverwmc on the desktop backend. All hooked up thru wired ethernet thru out the network. I am only using over the air signal ATSC as I have completely cut the chord with cable or satelite.
I can not get my KWORLD usb tuner to work with my ubuntu at the moment. I know there are PVR addons in frodo, but not the windows media center PVR. I wish I could get the usb tuner working in an linux enviroment. Then I could use a frodo based vidon.me xbmc with no issues and a different pvr front end. I could use mythtv or tvheadend to name a few linux PVR backends. But, alas I have had no luck with getting the usb tuner to work.