Can’t Figure Out How to Unlock iPhone 3GS on iOS 4.3.3

Hello Hubert, you should be note that unlocking an iPhone depends on what baseband you are in. If you have unlockable baseband, then you will be able to free your iPhone 3GS from its contracted mobile phone carrier using Ultrasn0w software-based unlocking tool. Additionally, JailbreakMe 3.0 does not support Ultrasn0w. Anyway, I would recommend you to check the baseband of your iPhone in order to know if you will be able to unlock it using Ultrasn0w 1.2.3. So far, Ultrasn0w is not working on the following basebands: 02.10.04 / 03.10.01 / 04.10.01 / 05.14.02 / 05.15.04 / 05.16.02. But in your case, since you are using an iPhone 3GS, you can update the baseband of your iPhone 3GS to iPad’s baseband so that you can unlock it with Ultrasn0w. However, you should be note that updating iPhone 3GS baseband to iPad’s 6.15.00 baseband will make you lose the GPS functionality of the device, and you will not be able to restore a stock firmware in the future. You can check some of the tutorials posted on below links on how to update iPhone 3GS baseband to iPad’s baseband 6.15.00 using Redsn0w:

• How to Update iPhone 3GS Baseband 05.14.02 to 06.15.00
• How to Update iPhone 3GS Baseband 05.15.04 to 06.15.00
• How to Update iPhone 3GS Baseband 05.16.01 to 06.15.00
• How to Update iPhone 3GS Baseband 05.16.02 to 06.15.00

I would also recommend you to use Redsn0w 0.9.6rc19 which you can get from here if you are on Mac or from this link if you are a Windows user. Since your device is running on jailbroken iOS 4.3.3, I would recommend you to restore your device on stock iOS 4.3.3, and you can do that with the help of iFaith SHSH Blobs Dumper - since Apple already stopped singing iOS 4.3.3 firmware. After restoring and jailbreaking iOS 4.3.3 on your iPhone 3GS with iPad baseband, you can now unlock it using Ultrasn0w 1.2.3.