I grudgingly had to jailbreak and unlock my 3GS when I moved from the US a couple of years ago as AT&T did not unlock out of contract phones at the time. As a result I had to 'upgrade' to the 06.15.00 baseband and use ultrasn0w. Now that redsn0w has finally made it possible to downgrade to the 05.13.04 baseband and AT&T unlocks out of contract phones I would like to factory reset my iPhone and set it up as new. I have tried looking all over the Internet to see if this is possible and though the topic has been covered in great detail I cannot find any specific information. Here are the questions that I would love to get answers to: 1 - Can I remove ultrasn0w and unjailbreak (by removing Cydia perhaps?) and if so how do I do so and when? Is this to be done before downgrading to 05.13.04 or after? 2 - Can I simply connect my phone to iTunes and restore it after I downgrade it to 05.13.04? If so then can I update it to the latest iOS version compatible with my phone? 3 - If this process is possible and successful then will my phone behave like any other non-jailbroken phone? I am afraid of bricking my phone as I have never played around with the jailbreaking process and would appreciate help!