I have an iphone 3gs which was not unlocked when I purchased it. I unlocked it via redsnow. I wanted to upgrade the phone to ios6 but since it was locked and jailbroken, I was not able to do it. Now I have lodged an unlock request to original carrier and they have given me instructions that my phone is cleared to be unlocked via itunes and that I must insert original sim that came with the phone. Whereas I don't have that original sim. My question is that is it ok to connect my phone to itunes and upgrade it. my phone will be upgraded or it could do any harm to my phone.