- 1). Jailbreak your iPhone. There are many different pieces of software for jailbreaking iPhones, depending on your operating system and iPhone model. Some can do it right on your iPhone, while others require software download.
- 2). Install Cydia. Cydia is the app store for jailbroken phones. Some builds have it built in, while others require a separate installation.
- 3). Search for "ultrasn0w" in Cydia. Download and install ultrasn0w. This will unlock your iPhone and allow you to use it with a non-3G SIM card.
- 4). Eject the SIM tray from your iPhone. On the 3G and 3GS it's along the top, but with the iPhone 4 it's on the side. Use a paper clip or pushpin to press the eject button. Insert the new SIM into the tray and reinsert it into the iPhone. You're now using your iPhone with a non-3G Sim card.
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