Simply connect your phone to iTunes and back up your data. Then, click the “Restore iPhone” button and follow the on-screen instructions. It’s a huge pain, but at least it’s better than having your shiny new iPhone turned into a big expensive iPod touch.
For those without access to a computer with iTunes right now, you’re unfortunately out of luck. We’ll update this post if anyone finds a way to fix the problems that doesn’t require a computer.