iPhone Dev team has released Redsnow 0.9.14b1 to downgrade the baseband 06.15.00 to 05.13.04 on iPhone 3GS so that you can install iOS 6 firmware and use the 3D Maps feature and voice guide navigation . It will also Unlock iPhone 3GS and give Full GPS Support on iOS 6 . If you updated to the iPad baseband to get an unlock for your iPhone 3GS , this is the chance to get back the GPS capabilities of your phone .
Steps to Downgrade iPhone 3GS 06.15.00 to 05.13.04 Baseband :
- First backup all your data on the iPhone 3GS using iTunes
- Now Download Redsn0w 0.9.14b1 on your Mac or PC
- Download the .ipsw file for the exact firmware you are running on your device . You can find which version of iOS you are running by going to Settings > General > About > Version
- Launch Redsnow in Administrator mode in PC
- Go to Extras > Select IPSW button and browse to the ipsw file downloaded in Step 3
- Redsn0w will verify the ipsw file and ask you whether if you have an older bootrom iPhone 3GS or a new one, read the on-screen instructions very, very carefully before you proceed
- Go back to Redsnow home page and click on Jailbreak button
- Redsnow will now process the ipsw file displaying Preparing the Jailbreak Data screen . After the process is complete you will get a set of different options. Simply check the Downgrade from iPad Baseband and Install Cydia options and click on Next button . Those who are already running a jailbroken iPhone 3GS need not check the Install Cydia option
- Follow onscreen instructions to put your iPhone 3GS in DFU mode
- Redsnow will run some random codes on the screen after which your iPhone 3GS will reboot and will be on the unlockable 05.13.04 baseband
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