The redsn0w jailbreak tool since it is now possible to downgrade baseband (modem firmware) on the iPhone 3G or iPhone 3GS to a lower version. The option is especially interesting for users who currently use an unlock on the basis of the iPad baseband 06.15.00, users of the base band 05.14.01, 05.14.02 or 05.15.04 which an unlock with ultrasn0w from want and users who perform a software unlock since they have carried out based on the iPad baseband officially via their phones have been able to unlock their provider. The use of the iPhone baseband to unlock was a source of problems, as did the GPS functionality for many users no longer function properly.
Downgrade Baseband 06.15 to 05.13.04 with redsn0w 0.9.14b1
You can use redsn0w 0.9.14b1 to perform an unlock on 05.13.04 if you currently have an unlock on the iPhone baseband 06.15.00. The baseband 05.13.04 is the latest baseband for iPhone 3G and iPhone 3G by the ultrasn0w unlock is supported. This baseband again you can make full use of the GPS functionality of the iPhone and again without problems to recover. To use the new option in redsn0w you first go to the menu Extras followed by Select IPSW and select the firmware currently on the iPhone is. Put drop your iPhone off by four seconds Home - and thePower button and keep using the Slide to power off functionality. Ga finally back to the home screen and select redsn0w Jailbreak . In the screens that follow you can then choose the option Downgrade from iPhone baseband . If your phone is already jailbroken, you have to uncheck the option that Cydia is installed.
Limited compatibility of redsn0w 0.9.14b1
It is also possible to downgrade to 5.13.04 if you currently baseband 05.14.01, 05.14.02 or 05.15.04 for iPhone 3G or have some 3G iPhones. The downgrade will take place through the iPad baseband 06.15.00 and not every iPhone 3G baseband, this in connection with newer NOR and RAM chips that Apple uses. More specifically, the baseband is not suitable for the 3G iPhones in or after week 34 of 2011 produced. You can recognize these devices to the 3rd, 4th and 5th digit of the serial number. If these figures are 134 or higher (xx134) then you can not use the new functionality to downgrade. If you like the new redsn0w functionality combined with a recent iPhone 3G would try to, then tap the ability to make calls lost.