Iphone Dev Team perform iPhone unlock by exploiting the iPhone Baseband but Apple tends to fix it in its next firmware update. The last time Apple had patched the baseband was in iOS 3.1.3 firmware which was later unlocked after iOS 4.0 and iOS 4.0.1 firmwares were released.
For those who want to upgrade their iPhone 4 on iOS 4.1 & 4.2 and experience the new iOS 4.1 features , 4.2 updates , still preserving their unlock then you can try the method given below . However remember that the upgrade will wipe your jailbreak and you have to jailbreak again using Limera1n or GreenPoison. Tutorial given in the site homepage.
**IMPORTANT : Remember to save your SHSH Blobs before you attempt any upgrade , or you may not revert back .
Steps to Upgrade to iOS 4.1 preserving Original Baseband :
- Install TinyUmbrella and exit iTunes
- Run Tiny Umbrella and Start TSS Servers as shown below
- If there is no error , proceed to step 4
- Now Start iTunes and select Restore as shown in the image below .
- Accept the upgrade and proceed to downloading .
- After completing the upgrade you may see the following error “The iPhone could not be restored. An unknown error occurred (10044).” Just ignore that and return to TinyUmbrella and click “Kick Device out of Recovery”
Thats it , you must see a new upgraded firmware without any change in the baseband. Please let us know how that worked out with you.
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