The screen faded back in. He was in the Korok Forest. The place that, on previous versions, ran at 15 frames per second and looked like a jagged mess.
You have a BreathOfTheWild_150 graphic pack selected. Fix: In Graphic Packs, filter by “Version” and select only those marked 1.6.0 or All Versions . botw update 160 work
To verify you have the correct version, look at the of the title screen or check the Software Information on your Switch Home Menu. The screen faded back in