The iPhone User Guide

A lot of people have downloaded iPhone 3.0 illegally and tried but it, and found it has too many bugs to be useable for now.

Here is how to downgrade - uninstall iPhone 3.0 to 2.2.1 Firmware.

1. Connect your iPhone to your Mac or PC and select your iPhone from the list of devices in iTunes
2. If iTunes does not detect your iPhone then you will need to put it in DFU (Device Firmware Upgrade) mode.
3. Browse the Summary Tab
4. Mac Users, Hold down Option and press the “Restore” button, Windows Users, Hold down Shift and press the Restore button
5. Now browse the folder where you have the iPhone firmware. Select the firmware & hit the restore button and cross your fingers for 5 minutes.
6. Ignore error message like 1011, 1013, 1015 (Actually the firmware 2.2.1 is already successfully installed)
7. Use QuickPWN 2.2.5 to Jailbreak iPhone Firmware 2.2.1

Steps to put iPhone in DFU mode

1. Connect your iPhone to your computer.
2. Turn iPhone off.
3. Hold power and home together for 10 seconds (exactly).
4. Release power but keep holding home until the computers beeps (observed on a PC) as a USB device is recognized.
5. A few seconds later iTunes should detect your iPhone.

If you encountered with error message like 1601, 1602, 1600 or anything else then try putting the iPhone into DFU mode and try again.