Unbelievable method to unlock with Ultrasn0w iPhone 3GS on iOS 6.1.3 baseband 05.16.08 (which is not supported by Ultrasn0w). To be honest I found the video on YouTube where the user ultimateidevicevids, showed interesting way to unlock 6.1.3 baseband with famous tool. Last time I showed you how to use Ultrasn0w on iOS 6.1.3 iPhone 4, 3GS with old (preserved) baseband but here below you will definatelly find something new. There are four phases to do. First you will need to jailbreak your device. Then to install iPad baseband (06.15.00). After - downgrade from iPad baseband and install Ultrasn0w to get the signal. Attention: As for me I didn't test this method and installing 06.15.00 may harm your device. So think twice before following steps below. This method is shown on AT&T iPhone to unlock it for T-Mobile. But if your device is locked to AT&T I have a better idea for you. Why spend your time and efforts together with the risk of corrupting the iPhone if you can buy AT&T iPhone unlock only for $9.99. Plus, your iPhone will be officially unlocked which means you can update iOS and baseband in iTunes and your device will be never be locked again. But if you decided to give a shot we can start.

How To Unlock iPhone 3GS iOS 6.1.3 Baseband 05.16.08

Note: This guide is not working for all 3GS models. It will work only if your device was made before the 34 week of 2011. To check it look at the third, the fourth and the fifth digits of the serial number. The third is a year (if there is 1 - it is 2011), the fourth and the fifth is a week. Be serious about that and check your compability. Otherwise your device may become a brick. Step 1. Download redsn0w and iOS 6.0 firmware file on your computer in the same folder or the desktop:

• Download iOS 6.0 IPSW file for iPhone 3GS.
• Download the latest redsn0w 0.9.15b3.

Step 2. Launch redsn0w as Administrator and go to Extras -> Select IPSW and select iOS 6.0 firmware you downloaded in step 1. The tool will ask if your iPhone is with new bootrom or with old. Again the serial will tell you this. If it was made after 44 week of 2009 the iPhone would be with the new bootrom. Step 3. Now go back to the main redsn0w window and click Jailbreak. Make sure to check Install Cydia only and click Next. Step 4. Turn off your device and enter DFU mode following steps on the screen. Step 5. The process begins, so give it 5 minutes to be finished. Step 6. After your device restarts turn it off again and got to Select IPSW on redsn0w again and specify it with iOS 6.0. Step 7. Next click Back and Jailbreak. Now be sure to uncheck Installl Cydia and select Install iPad Baseband. Click Yes and then Next. Step 8. Enter DFU mode and wait till the end of the process. Step 9. After your device restarts repeat Step 6. Step 10. Now click Jailbreak again and uncheck Install iPad baseband and select Downgrade iPad baseband. Step 11. Enter DFU and wait till the end of the downgrading. Step 12. If you have iPhone 3GS with older bootrom you will Cydia on your Home Screen. But if your are the user of the newer 3GS you will need to use Just Boot option in redsn0w or iBooty tool to boot your iPhone tethered and make Cydia to be working. So do it now. Step 13. After restarting you will see Cydia on your Home screen, launch it and wait till it will load files. Step 14. Now just go to Search and type Ultrasn0w. Step 15. Install Ultrasn0w. Step 16. Insert the Sim card you need to use (non supported) in iPhone. Step 17. Now just wait for 5 minutes to get a signal and make a call on just unlocked iPhone 3GS 05.16.08 with Ultrasn0w. Enjoy your free unlock and remember if your iPhone 3GS is newer model you will need to use Redsn0w Just Boot or iBooty every time it discharges or reboots. If it is with older iPhone is untethered jailbroken on 6.1.3. Here below you can see the video which I described above: Use comment section below if you tried this method. Get others know if it's working.