iOS 5.0.1 caused some major problems to those who wanted to jailbreak and unlock. Dev Team solved the jailbreak problems but ultrasn0w became incompatible with the new version of the iOS operating system.
Although MuscleNerd promised to fix the compatibility issues, this didn’t happen and ultrasn0w from the Dev Team repo is not compatible with iOS 5.0.1.
Even if Dev Team is not working on solving our problems, there are others who do and an unofficial method to make ultrasn0w compatible with iOS 5.0.1 has been released.
I am not using ultrasn0w, i haven’t tried this method so i can’t tell you if it’s 100% secure. Those who tested it said that it works, so proceed on your own risk.
Ultasn0w continues to unlock just the following basebands:
After you jailbroken your iPhone, install iFile from Cydia.
Install iFunbox or any other Windows/Mac program that allows you to access the systems files of your Apple devices.
Download commcenter compatible with iOS 5.0.1 here: http://hotfile.com/dl/136503056/d88e380/iPhone3Gs_5.0.1.rar.html and http://hotfile.com/dl/136503162/d8810a4/iPhone4_5.0.1.rar.html
Open the file downloaded below and then open the program that you use to connect to the system files of your Apple products and go to the following location: System/Library/Frameworks/CoreTelephony.Framework/Support
From that location you will delete the comcentreclassic file and you will upload the one you downloaded at Step 3.
Open iFile on your Apple device and go to System/Library/Frameworks/CoreTelephony.framework/Support/ where you will search for the comcentreclassic file.
Using iFile you will now edit the permissions of that file. To do this press the blue arrow in it’s right and in the permissions group you will set the following things by pressing on each option:
User: Mark writing, execution and reading
Group: mark reading and execution
Global: mark reading and execution
Install ultrasn0w from Cydia and restart your device. If you have tethered jailbreak do not forget to boot tethered.
After your iPhone restarts your phone should be unlocked.