I have purchased a used iphone 3gs on firmware 3.1.3 which I want to retain rather than updating to ios4xx Prior to my purchasing the phone it has been unlocked from its original network (02) in the UK by using Cydia. I would like to remove Cydia from the phone but if I do so will this relock the phone back to the original carrier 02? Alternatively, if I get 02 to unlock the phone for me via iTunes and then do a factory restore, will this in turn remove Cydia? Advice on my best my way of doing this and removing Cydia would be appreciated. Thanks in advance for suggestions and advice.