Old firmware on iPhone 3g. How best to jailbreak?

[hopoffbaby]

Hi All,

This is my first post on here. I have recently been given a iPhone 3G which hasn't been used for a while.

Its locked to O2 but I have a T-mobile contract sim that I would like to use in it.

From what I understand the software on it is quite old and I didn't want to update via iTunes and then not be able to unlock the phone for T-Mobile.

The software version is 2.2.1 (5H11) and baseband is 2.30.03.
My question to you is, what is the best method to get this phone as up-to-date as possible and have it unlocked at the same time???

I did read about the 4.1 jailbreak method but understand that you have to install the iPad baseband and that this is un-reversible. I didn't think this was ideal? What do you guy think?

Many Thanks,
hopoffbaby.

 

[iGaz]

I believe any baseband can be unlocked on the 3G. Please double check first before updating. In any case its the 3GS you need the iPad baseband for.

I wouldn't recommend updating to 4.xx as I've heard alot of people saying that the 3G is incredibly slow on iOS 4.