I just added horizontal splash screens to my iOS project which allows vertical also. Seems like they are ignored and I get a clipped vertical screen instead.
I’m still getting this issue in 4.15 on my ipad pro 12.9. Every time the splash screen loads up, it shows the correct landscape image for a split second and then switches to a squashed portrait image of my splash screen. Any help is greatly appreciated.
You need to edit the engine code (as of 4.16). The Unreal engine code mounts its own image (after the system splash) to cover further engine initialization. You need to prevent rotations during this period.
It’s annoying and an engine bug. Hopefully fixed in later versions would be good to get confirmation if that’s the case!