Samsung GS5 SM-G900I boot loop and black screen

[AC Question]

Does anyone know how I can fix these issues. The phone rarely boots past the samsung logo before restarting. When it does, it tends to have a black non responsive screen, although the buttons work.

I have lollipop 5.0 running on G900IDVU1BOJ1 Australian Optus build.

The phone isn't rooted.

I have tried all sorts of tutorials online, including cache wipes, factory resets, hard resets, draining all power and leaving for 10 minutes.