UltraSn0w 1.2.1 has been fixed to unlock iOS 4.3.1 on previously unlockable Basebands. These are the steps to unlock iOS 4.3.1 with UltraSn0w on iPhone 4 and iPhone 3GS. Before unlocking iOS 4.3.1 on iPhone 4 and iPhone 3GS, read the important part first.
We’ve pushed out the 4.3.1 compatibility fix for ultrasn0w in Cydia — it’s now at version 1.2.1. If you’re not already at 4.3.1 and you need the unlock, please be sure you understand how to get to 4.3.1 using a custom IPSW that doesn’t update your baseband.
This isn’t a new unlock! It’s to allow those who are already unlocked to use FW 4.3.1. It also fixes the signal bar issue for those who aren’t using the unlock but retain an older baseband intentionally.
AFTER INSTALLING ULTRASN0W 1.2.1, PLEASE REBOOT YOUR iPHONE using the normal “slide to power off” swipe. T-Mobile users in the USA also should disable 3G mode in Settings->General->Network.
- iOS 4.3.1 had broken the UltraSn0w. This UltraSn0w update just fixes the conflicts with iOS 4.3.1. There’s nothing new.
- No Newer Baseband support is added.
- Compatible Basebands: 01.59.00 | 04.26.08 | 05.11.07 | 05.12.01 | 05.13.04 | 06.15.00
- Not-Compatible Basebands: 02.10.04 | 03.10.01 | 04.10.01 | 05.14.02 | 05.15.04 (Dev-Team is working on Downgrade Baseband method)
- iPhone 3GS (not-compatible baseband) users can upgrade to 06.15.00 baseband which is unlockable (Here is How to). Upgrading your iPhone 3GS baseband to the 06.15.00 iPad baseband hack to unlock MAY cause you to lose your GPS!
Let’s Unlock iOS 4.3.1 with UltraSn0w Unlock on iPhone 4 and iPhone 3GS.
How to Unlock iOS 4.3.1 with UltraSn0w
***T-Mobile USA users please disable 3G network first. (Settings >General >Network and turn the “Enable 3G” switch to OFF.)
Your iPhone 4 or iPhone 3GS must already jailbroken on iOS 4.3.1. Jailbreak iOS 4.3.1 guides are linked at the bottom.
Assuming that your iPhone 4 or 3GS is jailbroken on iOS 4.3.1;
- Open the Cydia;
- Let the Cydia Load and Update if it prompts you;
- Go to Search tab and search for ultrasn0w and install it.
- Installing UltraSn0w will unlock iPhone 4 or iPhone 3GS iOS 4.3.1 with baseband 01.59.00 / 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00. Once the installation is completed, reboot your iPhone.
Voila! You have unlocked iOS 4.3.1 on iPhone 4 / 3GS with UltraSn0w and can use SIM from any carrier now.
How to Jailbreak iOS 4.3.1
- Jailbreak iOS 4.3.1 [All Guides]
- Jailbreak iPhone 4 / 3GS iOS 4.3.1 Untethered with RedSn0w 0.9.6 RC9 [Untethered]
- How to Jailbreak iOS 4.3.1 with PwnageTool 4.3 [Untethered]
- How to Jailbreak iPhone 4.3.1 Using Sn0wBreeze 2.5 [Untethered]