I'm having a similar problem. Just recently my Samsung Smart TV has been turning on to the HDMI channel my Pi is connected to, but it just shows a blank screen. When I off then on my box it loads Kodi then shortly afterwards goes black with no control from either my remote or phone app. I've been using the Pi successfully for nearly a year, so not sure why this has suddenly started happening.
I only have OpenElec installed up to Isengard and not a huge knowledge of the underlying code, so any ideas need to have some decent instructions included as if I'm a complete noob.
Many thanks for any help that can be given.