I didn't want to put all my issues in the Topic, so sorry it's a little vague.
History - I've been using Kodi since Isengard. Love it. I've been using LibreELEC since Jarvis (I believe). Started with a Pi 2, then a Pi 3. I waited to get a Pi 4 because the device was still new and had a lot of bugs. I knew I would want one though because it supports 4k video, has USB3, and has gigabit LAN. These are vast improvements and I am eager to make it work.
Current Setup - Rpi 4 4gb connected via microHDMI in HDMI0 to HDMI in on my TV. TV is an LG webOS TV OLED65C9PUA. Audio out is through the Digital Optical Out to a Denon AVR-591. LibreELEC release is 9.2.1. I have also gone into the LibreELEC settings and updated the "Bootloader EEPROM" and the "VIA USB3 Firmware)".
1 - I saw on the LibreELEC homepage that in order for the Pi4 to output in 4k 60hz, I needed to add a line to the config.txt file "hdmi_enable_4kp60=1". I have done this. However, Kodi seems to load up in 4k 30hz. The resolution is 3840x2160. I also have an option to output at 4096x2160 but it only outputs at 30hz too. It looks like the only way I can get true 60hz is by selecting the 1920x1080p resolution, which isn't 4k. Is this a known problem that is being worked on, or am I missing something? I did add an extra bump to the memory split thinking it might help (I have the 4gb version of the Rpi 4 after all). I also tried adding the "old" format to enable 4k too, just in case the "new" format wasn't working. Here is a copy of my config.txt file:
2 - The Kodi menus seem to "fracture" when navigating. By fracture, I choppy, stuttery, and breaking during the moving animation. Kind of like when a low bandwidth video stream starts to pixelate. It's more or less a visual annoyance than anything else. I've never seen it before on any previous versions of Rpi's or Kodi's. I suspect it might have to do with the refresh rate not being 60hz, but I've seen it when I drop the resolution down to 1080p too. Increasing the memory split didn't help either. As a "temporary" workaround I've gone into the skin settings and disabled the "slide animations". Now it fades rather than slide, but I still l occasionally see it when I'm navigating. Like when in the settings menu and I move around the highlighted option boxes, the animation of making them bigger to indicate it's selected cause the animation to sometimes stutter.
3 - This is mostly just informational... My router is broadcasting WiFi at 2.4G and 5G, however when I tried to connect my Rpi 4 to it the only option I saw was 2.4G. Is the Rpi 4 still only capable of the 2.4G range and not 5G? If it IS supposed to support 5G, how do I access it? It's not really a big deal because I have it connected with the wired LAN for the gigabit speed anyway.
4 - I have some 4k Blu-Rays stored on my home server I'd like to start streaming through this device. I've never tried it before so I'm a little lost. Inside the Kodi Player settings, there is an option under Discs for the Blu-Ray Playback mode. It's default is "simplified menu" but when I select to use the original menu it gives me a popup about needing Java installed. I realize this is Kodi talking and not specific to LibreELEC. But, is there a way to install Java to make this work? If not, that's ok, I'd just like to know.
I think that's it. For the most part I'm just concerned about the first 2 problems. Not getting 4k 60hz is sort of a game changer. Maybe it'll be working right when the next version of Kodi comes out? As for the weird effects I'm seeing while navigating, that might go away once I have a different skin installed. But I would think the default built-in skin shouldn't have any issues like that. When I feel up to it, I will try to set up a tripod and record it happening so you guys can see what's going on better (I just had hernia laparoscopic and don't have much motivation right now).
Thanks for your help. And thanks immensely to the LibreELEC staff for developing and maintaining this awesome OS!