Because now iOS 6.1.3 can't jailbreak, so please do not update to the 6.1.3, has been updated to the 6.1.3, please read the following instructions:
iPhone 4S the latest iOS system unable to unlock the 3G card, need to jailbreak after installation of 3G patches, but iOS 6.1.3 unable to jailbreak ,so if you want use iPhone 4S iOS 6.1.3 Work 3G Sim Card ,Please install 3G Activation Code , using FalWok Unlock Sim , but only supports the United States iPhone 4S Sprint and Verizon version of 3G card to use , and some kind 3G sim card go internet only using 2.7G(EDGE) network !
FalWok Unlock sim iPhone 4S activation card need to problem on Microsoft .NET Framework 2.0 Service Pack 2 or higher version. If it can't run, please download it first: Microsoft .
NET Framework 2.0 Service Pack 2 , http://www.microsoft.com/zh-cn/download/details.aspx?id=1639
The Instruction of the FalWok activation program: (download.html)
1.Please open the activation program, then connect your iPhone 4S into the PC.
(If something not compatibly, please close them, and add them to believable )
2.Click "Install"(安装补丁）, Then Choosing the right SIM card carrier. Note: Unicom（中国联通） is the 3G SIM card, CMCC（中国移动） is the 2G SIM card.
3. importation of FalWok 12 digit activation code, click the "OK"(绑定）,Then it is all OK ,your iPhone can use FalWok Unlock USA Sprint and Verizon .
You are done here! then wait 1-3min to see ur T-Mobile or ATT logo with signal.
If u waited more than 5min and still don’t see carrier logo , pop out the
sim/sim card and pop it back in or restart it couple time u should be fine. Also
google online for ur APN setting and change the APN setting for DATA MMS is a tricky part, google online for that.Thanks