How to successfully downgrade your iPhone OS 3.0 (any version) to 2.2.1 without carrier troubles?

Dear people,

Downgrading your iPhone from a certain OS 3.0 version back to 2.2.1 is a real pain in the ass.

First, if you just try to restore your iPhone you are confronted with an iTunes error no. 1013. It leaves your iPhone in recovery mode and after that it seems to be really impossible to get it running again.

The good news is: Don't panic! Don't panic at all. Just follow all these steps, and you are back again from where you starterd, with a working and jailbreakable iPhone.

Prerequisites

• A PC running Windows! (If you only have a mac, you'll need to run windows on it somehow. VMWare Fusion worked fine in my case, Boot Camp works probably better.)
• On this Windows-installation: iTunes 8.1.1, you can download that here: http://download.oldapps.com/iTunes/iTunesSetup811.exe
• An original iphone firmware version 2.2. (NOT 2.2.1, NO CUSTOM VERSION! Just original 2.2 build 5G77.) You can find it here http://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone/061-5828.20090127.aQLi8/iPhone1,2_2.2.1_5H11_Restore.ipsw
• QuickPWN 2.2.5-2 for Windows, you can download that here: http://quickpwn2-2-1.googlecode.com/files/QuickPwn-225-2.zip

NOTES

• Don't under any circumstance disconnect your iphone from your computer during these steps!
• If you screw up and you did something wrong, reset your iphone by pressing the home AND the power button for at least 15 seconds, then release both buttons, and then press the power button for 2 seconds.

ACTION!

1. Make sure iTunes 8.1.1 is installed in your windows environment. If you already have iTunes 8.2 installed, uninstall that first!
2. Connect the iPhone to your windows computer. If you are using VMWare, use the little USB-icon on the bottom right of the VMWare window (don't go full screen) to connect the iPhone to your virtual windows.
3. Start iTunes 8.1.1 on Windows. Click all notices away that may appear about your iphone.
4. Get your iPhone in DFU mode by
   A. Pressing the power AND the home button both for exactly 10 seconds
   B. Releasing the power button, but keep the home button pressed for exactly (at least!) another 10 seconds.
   C. If you succeeded, iTunes tells that the device is in recovery mode, but the display of your iPhone is BLACK.
5. In iTunes press and hold shift, while clicking on the restore (or recover) button in iTunes. Navigate to the firmware file you downloaded and select that. Wait for 5 minutes.
6. After a few minutes, you will get an iTunes 1013 error, and you iphone lands in recovery mode. Click the button in the error to make it disappear. At this point, start QuickPwn 2.2.5-2.
7. QuickPwn gives you instructions about resetting your phone. Do that, and wait for the iPhone to be restarted. If applicable, it will ask you to unlock your SIM with your pin-code. Do that. WARNING: DO NOT JAILBREAK YOUR IPHONE AT THIS POINT, just reset it.
8. Go back to iTunes, and wait until it recognizes your iPhone. It asks you if you want to activate it. Commit the activation, and wait until iTunes or your iPhone acknowledges that it's activated.
9. Restore your personal data with iTunes. (Can also be iTunes on your mac, if necessary.)
10. After that, use the iTunes 'update' button to update your iPhone OS to 2.2.1. It tells you to update iTunes to 8.2. Update iTunes, and iPhone OS.
11. Re-read and repeat steps 6 and 7.
12. You're done. If you want to jailbreak your iPhone, you need to uninstall iTunes 8.2, and reinstall 8.1.1. Then use QuickPwn to jailbreak.