Upgrading from iOS 4.2.1 to iOS 5.0.1 with Jailbreak & Unlocked baseband
Today I finally decided that it was time to upgrade my iPhone 4 from iOS 4 to iOS 5 since the untethered jailbreak was released. My iPhone 4 had firmware version 4.2.1 with baseband 0.1.59 still on it. This was not because I need the unlock but just because everyone has always said to keep it. iTunes backed up my phone completely and then I confirmed the backup worked properly. Alright time to upgrade I ran sn0wbreeze to remove the baseband in 5.0.1. All was going well until I got the firmware on my iPhone. I had run redsn0w to jailbreak the device which worked but after making it through the few new iPhone promote screen it would not let me restore my device the backup I had made earlier all iTunes was allowing me to do was create a new device. Well the only thing to do was roll back to iOS 4.2.1. Keeping with the standard I used sn0wbreeze to remove the baseband and then restored 4.2.1 the backup worked correctly. Good it worked now to restore back to 5.0.1, alright that worked and I did not run redsn0w yet and it let me restore from a backup.
tl;dr Make sure not to run redsn0w before you restore from backup.