[2.0 + 3G] Clearing things up
NOTE: Because this may be a concern to certain people, I would like to note that nothing in this post is information that was obtained by an inside Apple source or from employees of telco companies that have received prototype 3G iPhones. All of it has been obtained from reversing, ztringz, rumor websites, or information made available by Apple
It seems that many are confused about the 3G iPhone, 2.0, or both. Let me break it down.
According to the strings within a certain file found on a 2.0 beta ramdisk, one of which was seeded to regular developers and was not an internal Apple build, there are references to a bootloader 6.0. While this could either be a reference to a real bootloader 6.0, or just a condition that says "if bootloader >= 6.0, do blah, if not, then do blah". Also, it would be just silly to think that Apple wouldn't release a new bootloader. For one thing, there will obviously need to be major changes to the baseband and bootloader, probably other things to, in order to accommodate the 3G chip. Another thing is, well, Apple does not want people unlocking their iPhones!
'Special' 3G Activation iTunes
'StoreGeniusMode' and 'StoreActivationMode' are two special modes found in iTunes 7.6.3 and higher. There is no 'special' version of iTunes, per se. For instance, if you are a legit developer that has iTunes 7.7 on their Mac, because that is the only way you would get it, do the following:
1. Dock your iPhone
2. Close iTunes if it is open
3. Go to terminal
4. Type 'defaults write com.apple.iTunes StoreActivationMode -boolean YES' and press enter
5. Open iTunes, or restart it if you did not close it when I told you to
6. Look at iTunes. I will not go into too much detail, but I will say that if you have a legit activated iTunes, instead of showing your iPhone on the side bar like usual, it will tell you that your iPhone is already activated and that you should now disconnect it. My point is, this proves that there is no special version, it is just only in 7.6.3+
7. Right. You probably want to turn that off now don't you :P
8. Go into terminal and type 'defaults write com.apple.iTunes StoreActivationMode -boolean NO', press enter, and restart iTunes
9. Everything should be working again
3G on earlier builds (Downgrading it)
There is no publicly available information on this, so this section will be a bit lacking. I saw a post earlier about someone saying that their friend is offering unlocked 3G iPhones starting July 11. While I will not get into the possibility of that, I will say that their comment about possibly downgrading it to an exploitable iPhone1 firmware is not feasable. Remember all of those people who got their iPhones bricked when they accidently restored to an iTouch .ipsw when Pwnage was released? Well, according to an Engadget article, the 3G model number is n86ap. If this is true, then it will probably be just like if you tried restoring an iTouch ipsw to an iPhone - it just would not work, iTunes is smart like that :P Even if it was pwned, which would of course defeat the purpose, it would probably screw up the iPhone as the iTouch firmware does right now.
Hopefully this clears up a bit of the confusion. And no, the warning at the top does NOT imply the opposite of what it says. There is really a certain person that may be worried and I just did not want to give them the wrong idea, so don't speculate bullshit like that :P