Debian 9, drivers 375.39-1 with GTX580 : 4k missing


I use linux only as file server and for kodi. So i don’t use a GUI.
I had no issue when using a 1080p tv, but i switched to a 4k and can’t select a higher resolution than 1920x1080 in kodi.
So i started the nvidia-settings (using xterm in .xinitrc), and the correct resolution isn’t shown. I’m also having a hard time reading anything because somehow, the window isn’t full screen and the writings are unreadable @1080p.
The tv is a LG 65UH615V.
Here’s my Xorg log
And the nvidia-bug report

The final installation goes through an A/V amplifier, Pioneer VSX-923 (that supports 4k pass through). But i tried directly on the tv for setting it up.

I have no issue using a laptop on windows10.

Let me know if you need more infos, thank you in advance :)