I just bought a used 8GB iPhone on eBay, unlocked it and jailbroke it with winpwn, and am currently running 2.0.2 on it. Everything works flawlessly with the notable exception of App Store apps. They don't work. I can download and install them, but when I run them, they only run for a few seconds before they crash and I'm returned to the icon screen. Apps installed from Cydia and Installer work just fine. I've done all the obvious stuff: Turning the phone off/on, restarting the phone, uninstalling/reinstalling an application, syncing the phone, restoring the phone from a pwned backup, downgrading to 2.0 (from 2.0.2) and completely re-pwning the phone. None of it works.