The iPhone Dev Team has released an updated version of the ultrasn0w tool that adds support for iOS 5. You can use ultrasn0w to carrier unlock an iPhone. In other words, this is the tool you need if you want to use an AT&T iPhone with T-Mobile or another network.

In order to use ultrasn0w, you have to jailbreak your device. There’s a way to perform a tethered jailbreak on most devices running iOS 5, but you’ll need to connect your iPhone or iPad to a computer and run the jailbreak tool again every time you reboot. The only device that supports an untethered jailbreak right now is the iPhone 3GS with an older bootrom.

While ultrasn0w 1.2.4 now supports iOS 5, it does not work with newer basebands. In other words, if you’re already using ultrasn0w to unlock your device and you want to upgrade to iOS 5, you’ll need to use redsn0w to create a custom IPSW that preserves your older baseband.

You can currently do that with redsn0w for OS X. The Windows version will get that feature soon.

The latest version of ultrasn0w is available for download from the Cydia Store for jailbroken devices. While the new app adds support for iOS 5, it’s also backward compatible, so you can use it to unlock a device running iOS 4 as well — as long as you have a supported baseband.

Brad Linder

Brad Linder is editor of Liliputing and Mobiputing. He's been tinkering with mobile tech for decades and writing about it since...

26 replies on “Now you can unlock iPhones with iOS 5 using ultrasn0w”

    1. You can use the latest version of Redsn0w that is currently only available for Mac to create a custom IPSW and then use that on your iphone. Unfortunately the Windows version of Redsn0w is not out yet.

    1. me too and no one can tell me why i researched it like crazy so i ended up downgrading back to 4.2 to have it unlocked. so dumb…i followed all the instructions correctly but ultrasn0w does nothing for it and i was looking forward to using iCloud n iOS 5 :( let me know if you find out thanks!

  1. shit … ok my baseband is not supported and i already have a jailbroken 3gs running ios5.. what to do? help please/?

  2. Can anybody help? I have a 3gs old bootrom, jailbroken and unlocked a year ago. Two days ago, I  cleared and reset all data, download and installed ios5 from latest itunes 10.5, jailbroke it again yesterday with latest redsn0w on Mac. Its jailbroken sucessfully but Now there is no service. Please help…

    1. It changed the broadband when you upgraded it. I’m having the same problem. I would recommend that you do not change the broadband to an ipad’s since once you do it, you can never change it back..i’ll let you know if i come across a solution…

      1. Custom restore to 4.3 ipsw and this will downgrade the baseband to 4.10.1. Now u can unlock/jailbreak. Downside is u will have to use a gevey sim card. Good news is that the new ultra snow will unlock it and u won’t need the gevey very long.

        Now if u want to use ios5 use redsnow (the new version I forget the number) and create a custom ipsw file using iTunes ios5 original ipsw. Almost done! This will save the file as BB cistome ipsw. It’s ios5 without the updated baseband. Use iTunes to restore with the custom ipsw file.

  3. Is it necessary to reboot after installing? I did, and on reboot my 3GS was stuck on the apple logo and I had to restore

  4. Hi guys,  I have a question and it is probably already answered but if i could just get confirmation please.
    i have 3gs on bb 6.15 and ios 4.2.1. it have been unlocked by ultrasn0w.
    can i downgrade bb and factory restore to get the phone back to original condition?

  5. i did the jail break…ios 5.0 on windows , using redsnow 0.9.9b4…but then when i install ultrasnow 1.2.4 it goes recovery mode….please help…thank you

  6. ive done everything that has been on other websites on how to get service again and it still doesnt work and idk wat to do can someone please help?

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