Actualidad iPhone also have left you a gift the magi, if you have an iPhone 3G and upgraded the baseband to 15/06/2000 (baseband IPAD) we are going to teach you how to lower it back to 05.13.xx
Why is it a gift? If you've installed your phone baseband 06.15.1900 can not be restored with an official Apple firmware, so you can not jailbreak the new firmware until you see tools to create custom firmwares. Furthermore, the GPS stops working when you install the baseband 15/06/2000, which in most cases also be solved.
2. Fuzzyband running on the iPhone (without doing anything, just back out)
3. Run i-FunBox or disk and go to the route Applications / Fuzzyband.app paste the 06.15.00.cert ICE2 file you downloaded, if it does not copy the folder on your desktop, copy the file and upload it again.
4. Now unplug the computer and run iPhone Fuzzyband on your iPhone.
Congratulations, your iPhone can now update normally via iTunes.