I already tried 3 different hdmi cables. What kind of HDMI cable do you want me to try?
(all three have been tested to work fine with other appliances, including a rpi-2 with osmc).
The device is currently not plugged directly into the wall, I had a setup with the device plugged directly into the wall and it also happens in that config, since the wall plug is farther away then the short cable is long, a setup in that config is pretty annoying. Should I try to replace the supplied “powerbrick” with another one with similar spec?
The whole setup is about the same as I used sucessfully with the rpi-2 (which is even more vulnerable to power problems) since the first versions of raspbmc. The only difference are the osmc versions, vero 4k and the powerbrick used (rpi uses microusb power).