I can't open the file to upgrade the miner. What kind of software do you use to open it?
You don't need to open it. Go to your miner's Upgrade page, Image, Choose File, Flash image:
But I guess I fucked up, did the upgrade first instead of the update. Now i can't acces the miner via IP anymore because it doesnt start up.. how can i fix this?
That's the correct way to do it. There shouldn't be an issue unless you manually unplugged your miner while it was upgrading. Your IP address might've changed. Use an IP address scanner to find all devices on your network or use you router UI to find your antminer IP address.