Hey Demetris, I just wanted to let you know that I have LibreELEC-S8X2.arm-8.2.RC4-MXIII-PLUS.img.gz working great on 2 Tronsmart MXIII-PLUS's that I own.
Thanks for all the effort you have put in.
I do have 2 things that I have noted, that are really minor annoyances for which I have workarounds, but I would like to let you know them in case you would like to look into them at a later time.
First, I think there is something not quite right with your samba setup. When I go to the browser and choose SMB, I would assume that I should see my "WORKGROUP" workgroup at least, but nothing shows up. I get around this by "Adding source" and typing the machine names that I have setup, by hand. It does a good job of finding the machine by name. I don't even have to use the IP address.
Second issue, is that I have one older flat screen that has REALLY poor CECS. On this, when I first startup Libreelec on the Tronsmart, since it does a bad job of reporting correct resolution, I get "Invalid format" over and over until Kodi itself starts up, and then everything is OK. I don't know if there is any way of solving this, but I really don't need too, since KODI works fine, once it is running. I just cannot see any of the setup Libreelec is doing when I first burn an image including the Libreelec splash screens. Since my other flat screen is newer, it works just fine.
For what its worth, those are the only 2 issues I see and obviously minor annoyances at best.
EDIT: I think I might see why I am having trouble with my older flat screen. Apparently, a recent change to HardKernel changed the default U-BOOT to always be 1080p. My older flat screen only does at most 1080i. Unfortunately, I have no idea if there will ever be a fix.
EDIT2: I just solved the screen issue by going back to Android, and playing around with a couple rounds of rebooting after changing the screen resolution, and making sure that the Tronsmart logo splash screen comes up consistently. Then I restarted Libreelec, and magically the entire powerup and LE logo shows.