I am using an iPhone 4 with iOS 4.2.1 firmware. At the moment, it supports various SIM cards such as O2, Vodafone, T-Mobile, Orange, and even Tesco Mobile. I got this phone from a friend and I am uncertain if it’s a factory unlocked iPhone or not. Anyway, I am thinking to update this to the latest firmware. However, I am afraid that I might lose the ability to use this over other networks. Can anyone help me to determine if this is a factory unlocked iPhone? Thanks.
Asked by: Patrick from London
Step 1: Press the Settings from your iPhone homescreen to launch Settings Menu.
Step 2: Press General from Settings Menu.
Step 3: Now navigate to About from General Menu.
Step 4: Under About screen you can check iPhone firmware version under Version Label.
Step 5: Then scroll further down to check the baseband version of your iPhone under the Modem Firmware Label.
If you see baseband version 01.59.00 (iPhone 4 user) or 6.15.00 (iPhone 3G and iPhone 3GS) and you have Cydia and Ultrasn0w software installed, then you are using an iPhone which was unlocked using Ultrasn0w. Additionally, you can also unlock iPhone 4 using Gevey SIM. So check SIM tray if you have Gevey SIM on it.
If you are using a factory unlocked iPhone, then you don’t have to worry about updating your device to iTunes. Because it will remain unlocked no matter what firmware you install on it. And just in case if it’s get locked, you can use Gevey SIM Pro to unlock it again and rejailbreak it using Redsn0w.