As promised, the Dev-Team has just released the carrier unlock for iPhone 4.2.1 on the 3G and the 3GS for basebands later than 05.13.04.
Here’s how to use the Ultrasn0w unlock on your phone. Know that the Dev-Team does warn that if you have an old bootrom 3GS and are already unlockable, but want to get to 4.2.1 should hold off until the Dev-Team releases an “unofficial” bundle.
They also note that they will be releasing an update to RedSn0w later today for those who do not have Macs (and therefore cannot run PwnageTool) They say that the new RedSn0w will give you the option to update your baseband to 06.15 as well.
They do warn of a few things that come with downloading 6.15 and say to “do this at your own risk”:
– There is no way to come back down from 06.15, and there‚Äôs no hiding the baseband version from Apple. You‚Äôll be voiding your warranty in a very obvious way.
– If some future baseband comes out with a critical fix, you won‚Äôt be able to update to it if it remains down in the 05.xx sequence (then again, you wouldn‚Äôt update to it if you wanted to keep your unlock anyway).
– Starting with FW 4.2.1 if you have 06.15 on your iPhone you won‚Äôt ever be able to restore to stock firmware (it will fail). You‚Äôll need to only restore to custom IPSWs (then again, if you‚Äôre unlocker you should already be doing that).
– Certainly don‚Äôt update to 06.15 if you don‚Äôt need to! Only do this if you need the unlock and you‚Äôre stuck on 05.14 or 05.15, and you‚Äôre willing to assume the above risks.
That said: Back everything up, and know that you are doing this at your own risk. Please make absolute sure that you know what you are doing. We take no responsibility if you lose data or your phone in the process.
1) Download this IPSW
2) Run PwnageTool (Torrent – SHA1 Sum = adda6d882dce1b5117d01586037de289407e038a) to create your custom 4.1 IPSW. Tell it that you want to use the iPad baseband you just downloaded in step one.
3) Restore your iPhone to your new custom IPSW.
4) Launch Cydia and go to Cydia>Manage>Sources>Edit>Add
5) Then enter http://repo666.ultrasn0w.com
6) Press “Add Source”
7) After installation, search Ultrasn0w 1.2 and install the application. This will unlock your iPhone.
8) Restart your iPhone, and you should be unlocked.