New iPhone 3G, do I need to worry about unlocking?

[Skyy]

Hello,
tomorrow I will get my T-Mobile G1 exchanged for a iPhone 3G 8GB and I wonder if I need to worry about unlocking.

I only ask because my SIM Card was already used in the G1 and the guy from T-Mobile said normally they don't exchange phones but he can make an exception since the iPhone 3G is a "try out" phone.

That means it was lying around in the shop for about one month for customers to play around with it so it obviously has been activated in some way before.

How high are the chances that I need to worry about updating my Baseband as I don't want to make the phone lock me out...
And of course I want to Jailbreak it...

Thanks for help in advance!

[confucious]

Might help if you let us know what country you're in. Is T-Mobile the official carrier in your country? If not, is the phone officially unlocked?

[Skyy]

Thanks for the answer!
I live in Germany and T-Mobile distributes the iPhones here.
I can't say much about the phone itself yet, only as I mentioned that it's a iPhone 3g 8gb used in stores before, as I will get it tomorrow.

[confucious]

If you are using the phone with the official carrier only you do not need to unlock but if you do want to unlock (if you travel abroad and want to use a local SIM for example) then it's safer to keep your options open by not upgrading the BB.
But the shop should install the latest FW and set it up as a new phone so it won't be an option.
BlackRa1n will JB and BlackSn0w will unlock the latest BB but you should always check before upgrading as it usually takes a while before the JB is compatable and longer for an unlock.

[Skyy]

Alright, thanks for the infos! I rarely travel abroad so I don't think I'll use another SIM. And I didn't knew locked iPhones would accept any SIM aslong as they are from the official carrier, nice to know.