The 4.2.1 firmware is one of the stable firmware versions that can be jailbroken and unlocked and it is no wonder that you want to know about unlock iPhone 3G 4.2.1. Jailbreaking iPhone gives you the added advantage of using third party apps and tools using Cydia store, while unlocking iPhone allows you to use any SIM card with your iPhone irrespective of the carrier. Unlock iPhone 4.2 is easier if you choose the right unlocking method. You don’t have to spend several hours in trying to find the unlock solution because we have spent our time in finding the best solution that can unlock the iPhone.
What you should know about unlock iPhone 3G 4.2.1?

Untethered jailbreak is not available for 4.3.5 and 4.2.1 is the last known firmware version in the 4.x series to be jailbroken successfully in untethered mode. Several jailbreak software methods that were used to jailbreak 3.x versions couldn’t be updated to provide untethered jailbreak. If you are an unlocker, you should go for untethered jailbreak because with tethered jailbreak, you will lose both jailbreak and unlock if you don’t reboot iPhone using tethered boot utility.
There are a couple of different options available to help you to unlock iPhone 4.2, but not all of them are entirely reliable. Gevey unlocking method is quite popular with those who don’t want to jailbreak their iPhone for the purpose of unlocking it. Jailbreaking allows you to install some useful apps and tweaks, but if you don’t want jailbreaking at all, the SIM unlocking method provides unlocking solution. Some of the Gevey methods claim to unlock iPhone 3G, but it is explained clearly on the official website that Gevey Ultra is useful for jailbreaking iPhone 4 only.
Before you try to unlock iPhone 3G 5.0.1, you should pay attention to the firmware and baseband versions on your phone. Software based unlock provided by Ultrasn0w will work only if your iPhone has supported basebands. Otherwise, you have to find other ways to unlock the phone. With 4.2.1, it is possible to use free unlocking methods, but you should always be cautious if you want to use free unlocking.
Free unlock iPhone 3G 4.2.1 – do they work?
The hackers teams like iPhone Dev Team and Chronic Dev Team are behind the success of several jailbreak and unlock tools. If you want free unlock iPhone 3G 4.2.1, you should know that it is possible. Ultrasn0w is the most popular software based free unlock iPhone method developed by iPhone Dev Team. Initially, Ultrasn0w was developed to unlock all basebands, but the hackers found that it is difficult to extend baseband support beyond certain versions. There are rumors that Apple has bought these hackers so that they shouldn’t attempt to unlock anymore iPhone basebands. So, if your ipone 3G runs on one of the following basebands – 4.26.08, 05.11.07, 05.12.01, 05.13.04, or 06.15.00, it can be unlocked with Ultrasn0w.
In order to make unlock iPhone 3G to work on 4.2.1, you should change the baseband. The baseband version that comes with 4.2.1 is 05.15.04 which can’t be unlocked directly through Ultrasn0w. The work around is to use iPad baseband 06.15.00 on iPhone 3G so that Ultrasn0w can be used. Redsn0w jailbreak tool allows you to install iPad baseband on iPhone 3G, but it has some disadvantages. Your warranty will be certainly voided as you can’t go back to any previous point once you obtain 06.15 baseband on iPhone. You can’t update your firmware or baseband if future updates are signed with 05.xx basebands. Restoring to stock firmware is impossible once you get on 06.15 baseband. So, needless to say, free unlock iPhone 3G on 4.2.1 using Ultrasn0w works, but it is extremely dangerous to use this method.
How to use expert recommended software for unlock iPhone 3G 4.2.1?
The jailbreak and unlock experts don’t want to leave you behind and you can still unlock iPhone 3G on 4.2.1, but you should follow the method suggested by experts. Third party software to jailbreak and unlock iPhone 3G is the best possible solution in the given circumstances. You don’t have to use iPad baseband and even with 05.15.04 baseband, you can still jailbreak and unlock iPhone 3G running on 4.2.1. You just need to follow the below mentioned simple steps to use computer software that is reviewed positively by several experts:
- Step 1: Choose a reliable third party jailbreak and unlock provider and pay for the software.
- Step 2: Download the software and gain access to membership area.
- Step 3: Launch the software and use the visual guide to run iPhone 3G on 4.2.1
- Step 4: Leave the software to do its work and wait for a few minutes to get message that jailbreak is complete.
- Step 5: Click on next button and launch the unlocking module to unlock iPhone 3G 4.2.1 in complete untethered mode on any baseband version.

