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Depending on where you live, you might possibly be able to call your carrier and request an unlock. For most other people, it depends on the version of iPhone and the version of bootloader. The original iPhone can be unlocked irrespective of the firmware version that is on it. For the other iPhones, it depends... the latest boot version isn't unlockable right now, so if it's a 3GS on 3.1.3, probably no. If it's an older 3GS that's running a prior bootloader, then yes, using free software from the Dev Team, Geohot, etc..
 
Also your Baseband will be a issue as well. dev-team has said JB and unlock will be out shortly after WWDC and 4.0 is officially released I would wait for that.
 
I'm pretty sure that tutorial refers to a way to upgrade to 3.1.3 without updating the baseband. If you update through iTunes, it will automatically update the baseband and you will not be able to unlock (currently).

So I can downgrade to 3.1.3 using xcode, anyway I could use one of those modified ipsw's that are jailbroken to downgrade?
 
No you can't because when you updated to 4.0 you updated the baseband. Even if you downgrade you cant downgrade your baseband so you will have to wait until an unlock for the newest baseband is released.
 
So I can downgrade to 3.1.3 using xcode, anyway I could use one of those modified ipsw's that are jailbroken to downgrade?

Unlocking is solely dependent on the baseband. Period. Since you can't downgrade the baseband, you can't unlock. It has absolutely nothing to do with the OS (other than upgrading an OS would upgrade the baseband). So, again, your baseband is all that matters for an unlock.
 
Just find this AT&T store ! :D

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3GS.

But are you positive that it is impossible for me to unlock it?
How come I see tutorials on the web to unlock a 3GS under 3.1.3?
Like: http://www.redmondpie.com/unlock-iphone-3.1.3-3g-3gs-with-blacksn0w/

You cannot unlock the 3GS with 3.1.3 as of now, my father bought his iphone from at&t thinking he can use it in HK, right now it is sitting in his drawer while we wait for the dev team to release a new hack. :)

So just wait until they release a new hack for us, unlock your 3gs, then sell it.
 
I've got to ask. How come you know nothing about what can be unlocked but are running around with a 4.0 iphone?
 
Your auction is a total mess. Listing it as NEW and UNLOCKED and on 4.0 software, then in small print at the very bottom you retract all of the above? If you don't get negative feedback for that transaction it will be a miracle.
 
On eBay, phones sell more if they are unlocked, is it possible that I could unlock it myself?

I have a related question to this. Is it safe to go to mall technicians just to unlock you iPhone? I am not really sure if it's safe because some of them might think that it is stolen.
 
I have a related question to this. Is it safe to go to mall technicians just to unlock you iPhone? I am not really sure if it's safe because some of them might think that it is stolen.

Its probably safe but why pay for something you can do yourself in a few minutes?
All they use is free software downloaded online just like they rest of us here.
They dont perform anything more than whats available by The Dev Team or Geohot.
 
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