Definitely install a previous version of Itunes as the newest Itunes 11.1 conflicts with customs ISPWs. I didn't have a problem with Itunes 11.05. I used Snowbreeze to create my custom ISPW with 6.1.3 blob and resorted back to IOS 6.1.3 (tethered jailbreak). I then decided I wanted an untethered jailbreak, so I used Snowbreeze again with a 5.1.1 blob and had no issue resorting back to IOS 5.1.1.All is good.