1. Start your iTunes 8.2 & Connect your iPhone 3GS to computer via USB

2. Switch of your iPhone and put it in DFU mode with following instructions

- Click the Home + Power On button for 10 seconds exactly

- Release the power button and continue to click on Home

3. Following message will be displayed in iTunes 8.2. Click on “OK”

http://www.blogsdna.com/wp-content/uploads...in-dfu-mode.png

4. Now Press ALT or Shift key on keyboard and click on Restore button on iTunes

5. Locate & Select the original iPhone 3GS 3.0 firmware

http://www.blogsdna.com/wp-content/uploads...30-firmware.png

6. A Confirmation message will be displayer. Click on Restore

http://www.blogsdna.com/wp-content/uploads...estore-mode.png

7. A Restore Process will start. At the end of restore process following error message “Unknown error occurred (1015)” will be displayed.

http://www.blogsdna.com/wp-content/uploads...r-code-1015.png

8. Do not panic with above error message. You just need to ignore above error message and click on OK button

9. Download iRecovery for Mac (http://chronicdev.googlecode.com/files/iRecovery-Mac.zip) and iRecovery for Windows (http://www.ziddu.com/download/3366256/iRecoveryWin32.zip.html)

10. Extract connect of iRecovery on Desktop

http://www.blogsdna.com/wp-content/uploads...7/irecovery.png

11. Go to terminal on Mac and on Command prompt on Windows and type following command

cd Desktop

iRecovery -s

12. Once you see a Message entering in Recovery Mode, Starting command prompt on screen type following command

Fsboot

http://www.blogsdna.com/wp-content/uploads...mand-fsboot.png

13 Once the iPhone 3GS has been restarted, you see the “Emergency calls only” and You need to reactivate tour iPhone 3GS via iTunes

14. Either you can restore a backup or configure your iPhone 3GS as new phone and you are back to iPhone 3G 3.0 Firmware.

15. Now you can jailbreak your iPhone 3GS 3.0 with Purplera1n. Download Purplera1n from here (http://www.blogsdna.com/3880/download-purplera1n-rc2-for-windows-7-vista.htm) & Check out how to jailbreak guide for iPhone 3GS 3.0 (http://www.blogsdna.com/3867/how-to-jailbreak-iphone-3gs-os-30-with-purplera1n-on-windows.htm).