According to the promise and announced release date, iPhone Dev Team has released an update to its ultrasn0w unlock with compatibility of iOS 5. The new update of ultrasn0w 1.2.4 allow users to unlock their iPhone 4 and iPhone 3GS with supported basebands on Apple’s latest released iOS 5. As usual the new ultrasn0w 1.2.4 only unlocks the old supported basebands, means no new baseband in the list.
You can only unlock your device if you’re running on these basebands 4.26.08, 05.11.07, 05.12.01, 05.13.04, or 06.15.00 on the iPhone 3GS, or baseband 01.59.00 on the iPhone 4. Well don’t lose hope you can also unlock your iPhone 4 latest baseband of iOS 4.3.3 with Gevey Turbo SIM but both unlock solution works only on iOS 5 if you preserve your baseband while updating to iOS 5.
If you have not updated your iPhone 4 and iPhone 3GS to iOS 5 and you have the above mentioned baseband then you must go with Redsn0w 0.9.9b5 for Mac OS X and Sn0wbreeze For Windows both of the jailbreak tools allows you to preserve your baseband while updating to iOS 5 and at the current time both provides tethered only boot, except the few old bootroom iPhone 3GS. Again we are recommended you to must check out the baseband preservation methods which we have highlighted above in order to make less chances.
How To Unlock iPhone 4 & iPhone 3GS With Ultrasn0w 1.2.4 On iOS 5:
Step 1: First of all verify your baseband to the above mentioned baseband list.
Step 2: Update your iPhone 4 & iPhone 3GS to iOS 5 using Redsn0w 0.9.9b5 or Sn0wbreeze for Windows to preserve old baseband.
Step 3: Once you have done with jailbreak and baseband, head over to Cydia and search for ultrasn0w 1.2.4 and install it on your device
Step 4: Now test your unlock status by hooking any other non official carrier sim in to your iPhone.