Earlier, we covered how you can unlock your iPhone 3G/3GS on iOS 4.2 using the latest version of Ultrasn0w. As reported by some of iPhone 3G/3GS users, they experienced battery drain problem after upgrading the baseband to 06.15 for ultrasn0w unlocking. The iPhone Dev team has confirmed the issue and advised to use “Subscriber Artificial Module (SAM)” hack developed by @sbingner to resolve the battery issue.
The battery drain issue should only experienced by users who hacktiviate the iPhone. If you use legitimated SIM card (such as the one from AT&T) to activate the iPhone, you shouldn’t experience the issue.
Without proper activation, even your iPhone is unlocked via Ultrasn0w, it still constantly looks for a valid Push certificate via WiFi or over 3G network. This continual action significantly shortens your iPhone’s battery life.
To resolve the issue, @sbingner offers a free hack called “Subscriber Artificial Module (SAM)” that allows you to do official activation on an iPhone without a stock SIM. With official activation, that means you can gain full benefit of push applications and improve battery life.
How To Use SAM to Activate Your iPhone
I assume you’ve already jailbroken your iPhone by using redsn0w. To use SAM, you’ll need to install it via cydia and use an updated version of redsn0w to deactivate your iPhone. Follow these instructions to activate your iPhone with SAM.
Warning: The procedures only work on iPhone 3G and 3GS. Also if you’ve already used an official SIM card for activation, you DO NOT need to use SAM.
1. First, launch cydia on your iPhone and add the repository “http://repo.bingner.com”. If you do not know how to add the source repository, check out our cydia guide.
2. Tap on the “Bingner” source. You should locate two packages called “SAM” and “SAM Prefs”. Install both packages.
4. Connect your iPhone to computer and launch Redsn0w. You’ll then go over a similar jailbreak process as described in our jailbreak guide. However, please select “Deactivate” for the option screen. Just follow the on-screen instruction to go over the process. When complete, you’ll end up with an iPhone that reverts to a stock lockdownd for SAM to function.
5. On your iPhone, go to “Settings” -> “SAM”. Tap “De-activate iPhone”.
6. Next, launch iTunes and make sure your iPhone is connected to your computer. iTunes should then activate the iPhone properly. If it doesn’t work (e.g. Invalid SIM), you’ll need to manually select the appropriate carrier under one of the methods besides “Automatic” and click on a SIMID.
If you want to learn more about SAM, check out its official website.