Help. I have reached the end of the quest, but after picking up Dawnbreaker fall and get killed. Does anyone know a solution or cheat to avoid this bug?

Same here.

But I did hear that this is how the patch works. You die before you get far enough into the game for the performance issues to show ( Bethesda should replace some of it's testers ).

Possible solution: I had Lydia on 'Stay here' at the door way, I set her back to follow and just after picking up Dawnbreaker, before the screen white out and seeing Meridia, I pulled up the menus and tried fast travel; this did'nt work but I landed without dieing.

Now alive and able to progress.

Don't quit her ending dialogue quickly. Let it exit by itself. Otherwise, she pauses before teleporting you and you die. Happened to me the first time, and I don't have the patch. After I just let her speak, I was fine.