unity flickering sprites on iphone5 only

I have my game almost ready, and it's working fine on iphone 6 and iphone 4, 4s, but when I run it on iphone 5 this happens: https://www.youtube.com/watch?v=wS7olrGqbQA

Basically all sprites flicker, except the background texture. You can't even see any sprites up until 3 seconds in the video. I'm using unity 5.3.2f1, if that makes any difference. Please help, I tried playing with settings but nothing works.