someone check my unlock procedure please??

[mgh]

I have a 3GS that someone else unlocked. It now has 4.1, with 6.15.00 BB, using T-mobile SIM.
I want to install an application that needs 4.3, so looking to update and unlock again.

This is what I understand so far:

1. Uninstall itunes 10.4.
2. install itunes 10.2
3. back up iphone
4. Use Snowbreeze to create custom 4.3.3
4a. Check box "activate iphone"? Not sure about this step.
5. Open itunes, shift/click restore, browse to custom Snowbreeze 4.3.3
6. Install Ultrasnow via Cydia.

Will my phone be ready to use with T-Mobile SIM now?
Am I missing anything?

Thanks for any help.

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[Gregoris]

You would also need to select the option to preserve the baseband so you can then use ultrasn0w

 

[Jmills87]

You cannot restore 4.3.3 unless you have the SHSH saved for it.