Please Help?

[jakerbzz]

Hey, I just got an iPhone from my mom and here are the Specifications:

This is the info i have about the phone so far
Model: iPhone 3GS
first 5 digits of SN: 86111
iOS: 5.0.1
Baseband at the moment: 5.16.05

The iPhone 3GS is JB'ed untethered on 5.0.1

i want to unlock my phone for t-mobile but i know that i have to update my baseband to 6.15.00

Main Questions:
What are the EXACT consequences i will face if i update the baseband, and will it affect my calls, texts, etc?
What does it mean that the 6.15.00 BB update causes the GPS to not function properly?

IF someone would be kind and also give me a written TuT how to successfully unlock this phone? THANKS SO MUCH

 

[elitegamer767]

Updating to iPad baseband can cause your gps not to work if you want to unlock your phone without causing problems contact your network they may or may not charge but if they do it it's permanent and if you accidentally update your phone will still be unlocked

Sent from my T-Mobile UK iPhone 4S using iPF.net