iPhone Dev-Team has just announced on twitter that the updated version of Ultrasn0w (that is Ultrasn0w 1.2.1) has been released publicly for all current iPhone baseband unlockers.
The new Ultrasn0w 1.2.1 fixes the compatibility, signal bar, and some other issues on iPhone 4/iPhone 3GS, running on the old baseband, and untethered jailbroken on iOS 4.3.1 using new tools, Sn0wbreeze 2.5 and PwnageTool 4.3.
According to Ultrasn0w:
ultrasn0w updated to support 4.3.1 *for existing unlockers* (fixes signal bar issue too). Update #2: http://is.gd/AXmH8v
According to the Dev-Team:
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. There are lots of guides for this (like at iClarified.com).
This isn’t a new unlock! It’s to allow those who are already using ultrasn0w 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.
This Ultrasn0w will not unlock new iPhone baseband. It is an update to existing Ultrasn0w which fixes some bugs and issues on iOS 4.3.1 iPhone 4 and iPhone 3GS running on old baseband only.
In case you are wondering, this tool will unlock these preserved baseband only: 01.59.00 / 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00 which is jailbroken on iOS 4.3.1 using new jailbreak tools like Sn0wbreeze 2.5 for Windows or PwnageTool 4.3 for Mac.
Jailbreak iPhone 4/3GS on iOS 4.3.1 and Preserve Baseband
Only for iPhone 3GS: How to update your device to baseband 06.15.00: To unlock your iPhone 3GS with Ultrasn0w 1.2.1, first you must need to update it to 06.15.00 baseband and then jailbreak it on iOS 4.1 / iOS 4.2.1. So follow our complete step-by-step guide posted here (either with PwnageTool / or with Redsn0w ) before following the below guide. Once you have updated your iPhone 3GS to baseband 06.15.00, then you can follow the below steps.
Step 1: First you have to jailbreak your iPhone on iOS 4.3.1 firmware and preserve the old baseband using either Sn0wbreeze (if you are on Windows) or PwnageTool (if you are on Mac). The guide to jailbreak iPhone on iOS 4.3.1 while preserving baseband is posted below:
Unlock iPhone 4 / iPhone 3GS Baseband on iOS 4.3.1
Step 2: Once you have successfully jailbroken your device, now you can unlock your iPhone on the supported baseband using Ultrasn0w 1.2.1 from Cydia.
- Start “Cydia” on your iPhone
- Tap on “Manage” tab at the bottom and then on “Sources”
- Tap on “Edit” button at the top right and then on “Add”
- It will now prompt you to “Enter Cydia/APT URL”. In that box, type “http://repo666.ultrasn0w.com” and then select “Add Source”
- Now tap on the “Return to Cydia” button and then tap on “Done” button at the top right
- Once the update is successfully completed. In Cydia, search for “Ultrasn0w 1.2.1″ and install this app. This app will automatically unlock your iPhone baseband and then you will be able to use it on any carrier you want.
Step 3: Once the installation of Ultrasn0w is complete, then restart your iPhone. Now you will have a fully unlocked iPhone 4 / iPhone 3GS baseband on iOS 4.3.1 firmware.