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There is no software unlock for 2.2.1, so the answer is neither.

2.2.1 comes with baseband 2.30 for which there isn't an unlock. You might be able to downgrade to 2.28 if you're lucky - search for forum for threads about downgrading 2.30 to 2.28, but you'll only be able to do that if you have bootloader v5.8
 
It doesn't matter. 2.2.1 is a thing of the past. The unlock and jailbreak for 3.0 will be released tomorrow by the Dev Team. It will easily unlock ANY iPhone 3G. Just be patient til tomorrow (today). 🙂
 
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