Okay... I've done this a few times and I have come up with a 100% way to downgrade from any 3.0/3.1 firmware back to 2.2.1 without hassles. 1. Download PwnageTool 2.2.5 for Mac 2. Follow the on-screen instructions to pwn your iPhone (make sure not to check "Activate iPhone") 3. Use PwnageTool to help you get in DFU mode and restore to your custom firmware. 4. Your iPhone should downgrade to 2.2.1 really easily with iTunes 8.2.1 You can either leave it at that (if you want to be jailbroken). Simply jailbreaking without installing Cydia or Installer would probably be fine for most people. For those who wish not to be jailbroken, you still have to do the steps above in order to downgrade to a non-jailbroken iPhone. Now we'll need to re-restore your iPhone to the official 2.2.1 firmware. Follow the next instructions: 5. Option-Click Restore and choose the *official* 2.2.1 firmware 6. It will look like it's installing 2.2.1, but it will finish with an error (If you have an iPhone 3G). This is normal. Here's the trickiest part. You need Windows for the next step. Note, this step is only for iPhone 3G users. 1. Download QuickPwn 2.2.5 for Windows and plug in your iPhone. 2. Now it will ask you to hold down Power and Home for 15 seconds. Do that. 3. Your iPhone will now boot up Then you should be all set. I hope this is helpful.