Im new to this (i) world, and totally confused on how to unlock a new iPhone 3GS for my friend. I actually need to only unlock it, but I guess for that jailbreak is also necessary as I read in most places. The Phone is 3GS running iOS 4.3.3 (8J2) with 8GB and baseband version 05.16.02.. I have access only to a windows PC and need to unlock it, jailbreak only if its vital for the unlock. Have iTunes 10.3.1.55 installed. Also will I risk anything on the unlock, could somebody help me with the softwares and procedure please? Thanks a lot!!

You will have to install the iPad baseband in order to unlock, to do that, download redsn0w from blog.iphone-dev.org, the firmware (4.3.3) from Firmware - The iPhone Wiki and follow the instructions.

Once you have Cydia, just search ultrasn0w and install.

Originally Posted by element

You will have to install the iPad baseband in order to unlock, to do that, download redsn0w from blog.iphone-dev.org, the firmware (4.3.3) from Firmware - The iPhone Wiki and follow the instructions.

Once you have Cydia, just search ultrasn0w and install.

It's worth mention that while 95% of people installing the iPad baseband have no issues, there is a small percentage of people who are unable to use their GPS after they have upgraded to this baseband. Secondarily, once you upgrade to this baseband it is no longer possible to restore a standard iOS firmware to your device -- you must create custom firmware that does not include the baseband or you will be stuck in recovery mode and will need to reflash. Last but not least, this is a (so far) permanent switch. Once you go to the iPad baseband, you CAN NOT downgrade OR upgrade the baseband to any currently released revisions.

Not trying to dissuade you from doing this, but wanted to be clear about the caveats and strings that were attached to make sure you knew what the ultimate outcome would be.

Oops, thanks n1ckn4m3, totally forgot to mention that, my bad!

Can you please inform me if I can install the 4.2.1 with the same way?

Originally Posted by tas1020

Can you please inform me if I can install the 4.2.1 with the same way?

Probably not.
Read up about SHSH blobs, these are used by Apple as a way of blocking downgrade (for your model phone, they only block downgrade of the OS, downgrade of baseband is blocked using another security technique)
If you don't have a saved 4.2.1 SHSH blob (Apple no longer issues this blob) then you can NEVER load 4.2.1 on your phone again.

You cant unlock without jailbreaking, first of all. You have to jailbreak using redsn0w then unlock it by downloading ultrasn0w from cydia.There re a lot of online guides out there, or if you want I can do it for you online. For your iphone if you unlock will probably loose waranty, will not be able to restore to normal itunes firmware , and maybe have gps problems.That is all

can anyone confirm if these are still the most up to date methods?

Confirmed.

Originally Posted by n1ckn4m3

Confirmed.

n1ckn4m3, where is the fundament of this theme. Every body must upgrade to 06.15.00. I do not understand it why. never will be another solution without damage the Gps of the iphone 3gs? Regards.