HDMI disconnects as soon as Kodi loads

    Hi!

    I've been using Libreelec installed on a Zotac ZBOX-CI660NANO (specs: https://www.zotac.com/us/product/mini_pcs/ci660-nano#spec) with an old Samsung smart TV without any issues but only with 1280x720 resolution. It defaulted to that and I didn't notice at the time altough it was a FHD TV.

    I changed the TV to a Hisense H40B5600. When I plugged in it defaulted to 1024x768 resolution and it couldn't be set higher. After some time I figured out that the problem was that the aspect ratio on the TV was set to automatic and somehow it defaulted to 4:3 with Kodi. When I forced 16:9 on the TV it allowed me to change the resolution. There is two option for 1080p and there is 1080i as well. I changed the resolution to 1080i since that is what my TV defaults to when I use a set-top box from the TV provider (1080i @ 50Hz).

    First it seemed that it works but when I started a movie and wanted to go back to the menu the HDMI disconnected and it didn't connect until I restarted the miniPC. After trying again the same issue arised. Then I tried to change the resolutions and framerate (from 60 to 50) and nothing helped. Every time I changed it, the hdmi cable had to be removed and plugged in again to display anything. (Note that the TV didn't say the HDMI was removed, it's just that there was no signal. When I unplugged it, it always had the message, that it was unplugged). I bought a brand new high speed HDMI cable but the issue remained. I was trying the different resolutions but when I went back to 1080i@50Hz it stuck and there were no signal ever again. I can't change the resolution on the HTML page either. When I try and press Save the display never comes back and once I restart it, it goes back to 1080i@50Hz. Libreelec is online and everything seems to work, it's just that there is no HDMI signal. The miniPC worked before providing 1080p/i content and the TV also works with my computer and the set-top box displaying 1080p. When I restart the miniPC it displays the Zotac logo then the LibreELEC logo and when it loads, the signal is gone.

    Tl;dr: Once Libreelec loads, the TV loses the HDMI signal.

    Here's the log after restarting the miniPC:

    http://ix.io/4Jqw

    I'd have a look for updated BIOS/firmware for the box, and perhaps think about running "getedid create" once the HDMI connection is up and working as this will force the kernel DRM subsystem to see the TV as connected all the time (even if it's not) which might help with HDMI stability (or it might not). I'd also think about trying other HDMI ports on the TV if it has some?. Also note that Kodi only outputs progressive so even if 1080i resolutions in EDID data they aren't usable. If you need to play interlaced material: enable adjust-refresh with the mode whitelist configured for 1080p @ 60/59.94/50/24/23.976 and enable refresh rate doubling so 25Hz material plays at 50Hz. With interlaced media this allows Kodi to render each interlaced half-frame in its own progressive single-frame.

    Thanks for the suggestions, unfortunatley nothing seems to help. I could bring back the menu and changed the resolution to 1080p, 720p etc. I tried every framrate option. I can use the menu but it disconnects when I start something and I want to exit back to the menu or the movie/episode ends. I use Kore on an android phone to control it, since the box doesn't support HDMI CEC . If the last movie/show didn't finished ie did not exited back to the menu, I can switch to another movie/episode and it works, but everytime I exit the menu the HDMI signal is lost.

    The box has the latest BIOS, I tried both HDMI ports, even tried another TV and it behaves the same. I tried getedid create, but the issue remained. When I tried getedid delete, the resolution reverted back to 1024x768 and everything worked fine with that resolution, but with only that. I only get signal back when I reboot the system.