iOS4 has GM’d, but Apple is yet to finalize their Game Center app. Currently, there are two different versions of iOS 4.0. Firstly, the publicly available version and an developer’s version. The developers version is identical to the official update, but includes the Game Center app for developers. Unfortunately, tools like redsn0w, sn0wbreeze and PwnageTool don’t support the developers IPSW. Fortunately, PwnageTool is incredibly customizable for patching firmware, so a few customizations makes it accept the developers IPSW.
1) Download and extract PwnageTool 4.01
2) View the package contents of PwnageTool.app and browse to PwnageTool.app/Contents/Resources/FirmwareBundles/<Your iPhone/iPod firmware version>.bundle
3) Within this bundle is an Info.plist, open it and make the following modifications to the following keys:
3a) RootFilesystem: needs to match the root FS dmg filename in the developer IPSW. Find this by opening the IPSW with a ZIP application and find the filename of the DMG that is approximately 300-400MB in size (it should be something like xxx-xxxx-xxx.dmg)
3b) RootFilesystemKey: each root FS is encrypted. Finding the key is difficult. Instead, search for the DMG filename in Google and you should find a few places that host the key for that particular DMG.
3c) RootFilesystemMountVolume: usually this is something like ApexXXXXX.iPhoneOS. Change this to ApexXXXXX.iPhoneDeveloperOS.
3d) SHA1: this needs to match the SHA1 of the developer IPSW. You can find this by using the command “openssl sha1 <IPSW filename>”
4) Now you can save the Info.plist, open up PwnageTool and select the developer IPSW. Hooray!