First off sorry if this has been posted, I tried to post it on my iPhone before but don't think it worked. To cut a long story short, I sold my 3G on ebay. The buyer has requested me to keep 2.2.1 on so he can unlock it. Can i upgrade to 3.0 then downgrade before I post it? I don't know much about this unlocking business. My worry is I have heard that once you download 3.0 you can't go back to a earlier firmware. Also even if you can, by putting 3.0 on my phone could it do anything that would stop it being unlocked? Even if i did go back to 2.2.1? Help would be appreciated.