I think it´'s a problem with the TV, but i will try the HDMI 2.0 Cable today and post the results here.
Hi, if you tried with 3 different HDMI cables, could be the TV (HDMI connector, EDID chip). Another idea, if you have around another TV, preferably HD-ready, connect the RPi to that TV, and if working, save the TV EDID data (SSH - run "getedid create"). In this way, the LE will use always the EDID "backup" instead to try to read it from TV. Always start the TV before power up the RPi. I had issues with EDID detection if the TV was in StBy when the RPi booted (resolved by "getedid create").