Today Dev Team has released a new version of redsn0w which allows iDevice owners to downgrade the 06.15.00 iPad baseband that was installed on the iPhone 3G and iPhone 3GS. The downgrade is done to the 05.13.04 baseband which can be decoded using the latest version of ultrasn0w, but it also allows you to use the GPS of your terminals without using an internet connection to locate in the Maps application or other similar applications.
This solution works on any version of iOS and it can ONLY be used on iPhone 3G/3GS, for iPhone 4/4S you cannot downgrade the baseband at the moment. You also cannot downgrade from another iPhone 3G/3GS baseband to the 05.13.04 baseband, but you can update to the iPad 06.15.00 baseband using this tutorial and then you can downgrade to the 05.13.04 baseband using the tutorial in this article. It is important to remember that the baseband of the iPad tablet DOES NOT WORK with the iPhone 3GS terminals released after the 24th week of 2011. More specifically, the iPhone 3GS terminals that have the serial number (you can find it in Settings>General>About>Serial Number) the first 5 digits in a construction like this xx134 or higher I cannot install the baseband 06.15.00 of the iPad tablet because the terminal will be permanently damaged because this baseband cannot be installed on those devices.
Step 1
Download the latest version of redsn0w available here.
Download from here a corresponding ipsw of the iOS version installed in your iDevices.
Step 2
Connect the terminal to PC/Mac. In Windows 7/Vista go to the folder where you downloaded redsn0w, right click on the executable, select Properties and from the newly opened menu go to Compatibility and tick Run this program in compatibility mode for then select Windows XP, Press Apply and then ok. If you do not follow the correct step, you will not be able to start the tethered terminal. On Mac/Windows redsn0w 0.9.14 beta 1), press the button Extrasthen Select IPSW and select the ipsw downloaded in step 2.
Step 3
Lock your iPhone using the Lock button. Hold down the lock button for a few seconds until the red slider appears, drag it from left to right and the terminal will close. This step is important to the process, and if you don't do it you won't be able to use redsnw0w to downgrade baseband.
Step 4
Enter the iPhone in DFU Mode:
- press the Lock button for 3 seconds;
- without letting go of the Lock button, press the Home button and keep it pressed for another 10 seconds;
- release the Lock button and keep pressing the Home button for another 10 seconds;
Your iPhone should be in DFU Mode, the computer playing a sound when the device connects.
Step 5
In redsn0w, return to the main menu where you choose the option jailbreak.
Step 6
In the new menu, check the option Downgrade from iPad baseband and uncheck the option to install Cydia if you jailbreak over an existing one. If you haven't jailbroken, select the option to install Cydia.
The baseband installation process will take quite a while, and the procedure Flashing Baseband it will last between 3 and 8 minutes, so you have to be patient until it ends. After finishing the process and restarting the iDevice you should have a signal, if ultrasn0w was already installed, and in the menu Settings>General>modem firmware you should have the value 05.13.04.
If after performing the process the baseband is not changed, follow it again. If after performing the process you have no signal, reinstall mobilesubstrate and ultrasn0w from Cydia. If after reinstalling the two packages your terminal does not reset, reset it yourself to be able to complete the process.
This baseband can be updated during a normal update process through iTunes, so be careful to only use custom ipsws to keep it at the initial value, otherwise you have to update again to the 06.15.00 baseband and again downgraded to 05.13.04.
