Recently I decided I didn't to be jailbroken so I went to do the process on iTunes on my PC where I clicked restore and a message would appear about backing up my contents. I did and as the time passed a message came up saying my iphone couldn't be restored. I'm still jailbroken and have all my stuff but I want to unjailbreak. Note again I have an iPhone 3GS on ios 6.1.3 and I used a custom ipsw when I jailbroke.
Read more: Unjailbreaking iPhone 3GS custom ipsw?