Apple periodically launches new versions of iphone firmware so that the users can enjoy more benefits and more features with the added advantage of the previous bug fixes. But if you have upgraded to latest version of the iphone OS 3.0, then there is quite some probability that you will encounter an error if and only if you have used illegal means such as jailbreaking. Apple has launched this new firmware to counter the illegal use of iphone applications. Now if you encounter any problem then the only solution left with you is to downgrade to the earlier stable versions of the iphone.
Downgrade iPhone Firmware 3.0 To 2.x.x
�*** The first thing you need to do is to enter in the DFU mode. You can do this by switching off the iphone and pressing and holding the power and the home button for atleast 10 seconds and now release the power button but keep pressing the home button until iphone is detected as a USB by the computer.
�*** The conventional method is to use itunes and downgrade to the previous version of iphone firmware but this would cause some errors because iTunes is unable to restore-back from the newer 3.0 baseband.
�*** To eliminate this problem you will have to download QuickPWN, the download to which is given at the end of this page.
�*** Now install and launch the new application and use that to downgrade to the previous version of the firmware. I guess that will be all on how to downgrade iphone firmware.
The download link to the windows and the mac version of the application are given below.
Download QuickPWN 2.2.5 for Windows
Download QuickPWN 2.2.5 for MAC