https://bugs.winehq.org/show_bug.cgi?id=25624
--- Comment #14 from hanska2@luukku.com --- Ok I got this pretty much solved.
I installed new lol.
You don't need to download or override anything.When you run the installer But 1st launch of lol can easily take 2-3min. And you only see the league of legends logo on screen. I quess it's downloading something background.
I didnt let it upgrade into full game. That would take time.
But I have seen the black retangle issue. It should be solved with overriding dxcompiler43.
It needs HLSL ascii or something like that (console spams messages).