How to Fix SIM Card Inserted in this iPhone Does Not Appear to Be Supported Error?

Hello Eduardo, you don’t need to downgrade the firmware of you iPhone as the SAM itself can fix it. To "The SIM card inserted in this iPhone does not appear to be supported" error all you need to do is launch Settings and navigate to General -> About to check you MODEL number. Once you got your mobile number, launch Google on your desktop and search where your iPhone is locked to (i.e. AT&T -United States). Back to your iPhone, launch Settings and navigate to SAM -> Utilities and then followed by tapping on Revert Lockdown to Stock button. From there, you will see Stockification Success message. If you get a Stockification Failure message then it means that the SAM installed on your iPhone is not the right version for your device. Therefore you should uninstall it and install it. (For those who aren’t aware, you can download SAM through http://repo.bingner.com repository)

Now, tap on SAM button and followed by tapping on Method menu and tap on By Bundle Name option form the list. Then tap on SAM option again and then tap on the Bundle menu and choose where your iPhone is locked to (i.e. ATT_US, Bell_ca, etc…). Now, go to SIM ID menu and choose your SIM ID, choose the first option if you don’t know your SIM ID. Once you have successfully setup your Method, Bundle, and SIM ID, go to More Information menu. You will see ActivationState as Unactivated. To activate it, you have to connect your iPhone to your PC or Mac and launch iTunes. Make sure that your computer is connected to Internet as your iTunes will be generating legitimate activation packets for your iPhone in order to authenticate your info with Apple servers. Once done, you will see your ActivationState as WildcardActivated.You can follow this step by step guide for detailed instructions and screenshots on how to fix SIM card inserted in this iPhone does appear to be supported error.