I create a blueprint-only project (with no content, mobile/tablet and max quality) and push to a , the entire screen is black. However, if I turn off the MobileHDR setting, then the game renders correctly.
I have tried this with my own project as well and noticed that UMG still renders fine. The game is running, but everything under the UMG layer is black.
Unreal Engine version is 4.16.3, device model number is GT-I9505 and device profiles picks this up as an “Android_Adreno320”. Texture format pushed to device is ATC.
This was last working in 4.14.3, but I have not tested it in 4.15.