not sure if this helps
all was working until update
I have same Problem with 64 Black screen tried it on 5 different TV's
I do get sound though
I USE i5 and intel 4600 Graphics
50 Sony 4k TV
24 Sony PS3 TV
55 Samsung
Using Displayport to HDMI Cable
Also Tried another Fresh USB Build no Upgrade and got the same thing..
Also took another pc that i have fresh build with HDMI and same thing...
Also installed the fresh build on i3 intel HD laptop and same thing...
If i go to advanced emulation setting then go to 64 libretto graphics look weak but it does work.... on all TV's and all PC's
Hope this helps fix issue
