Downgrade iPhone 2G 3.1.3 or 3.1.2 or 3.0 to 2.0

Downgrade iPhone 2G 3.1.3 or 3.1.2 or 3.0 to 2.0

Alot of people failed and received error message when doing Downgrade iPhone 2G 3.1.3 or 3.1.2 or 3.0 to 2.0, the key success of this downgrade lies on iTunes, please use iTunes 8.2, i am 100% sure it will be successful.
Omplete guide as below

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,

Mac Users,

Hold down Option and press the “Restore” button

Windows Users,

Hold down Shift and press the Restore button

4. Now browse the folder where you have the iPhone firmware.Select the firmware & hit the restore button and cross your fingers for 5 minutes.

5. Ignore error message like 1011, 1013, 1015 (Actually the firmware 2.2.1 is already successfully installed)

6. 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.

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