How to Downgrade iPhone 3GS to iOS 4.1 for Untethered Jailbreak and Unlock Baseband 6.15.00
Did you accidentally try to update your iPhone 3GS with baseband 6.15.00 to iOS 4.3.5 and then now you’re stuck on recovery? You know there’s no untethered jailbreak unavailable for iOS 4.3.5 and Apple doesn’t allow you to downgrade to earlier iOS versions unless you have your SHSH blobs saved.
UPDATE: Forget about installing iPad baseband or hacking your iPhone, make it officially unlocked here.
Thankfully, there’s still a resolution for this issue. Oddly, Apple is silently signing iOS 4.1 for 3GS which means you can downgrade to this version and have an untethered jailbreak.
Here are the steps:
1. Download iOS 4.1 firmware for iPhone 3GS from here.
2. Download sn0wbreeze 2.1 from here.
3. Launch sn0wbreeze and build a custom firmware (for beginners choose simple mode). You can also download iOS 4.1 hacktivated custom firmware from here. Once done, iREB will guide you on how to pawn-DFU your iPhone to allow it to accept custom firmware. Simply follow the on-screen instructions.
Note: You can also use redsn0w 0.9.6rc17 to pawn DFU your iPhone.
4. Check to make sure your host file will only point to Apple server. If you’ve used TinyUmbrella before, there’s a chance that the host file is set to Saurik’s server. A clean host file will look something like this:
5. To edit your host file, go to C:\WINDOWS\system32\drivers\etc. Right click ‘hosts’ file and open it with Notepad (on Windows 7 or Vista, right click and choose Run as Administrator). Remove any line that shows gs.apple.com
6. Launch iTunes, click Shift+Restore and point to the custom firmware.
7. Sit back and relax while iTunes begin restoring your iPhone.
8. Your iPhone is already in jailbroken state (Cydia installed) once restore is complete. You can now unlock it with ultrasn0w.
Any issues? Leave your comments below.
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17 Comments to “How to Downgrade iPhone 3GS to iOS 4.1 for Untethered Jailbreak and Unlock Baseband 6.15.00”
is this method really safe? This is the first post I see on downgrading iphone and the baseband.
it doesn't downgrade the baseband, only iOS
I followed the steps, and the Iphone was successfuly downgraded to 4.1. and jailbraked with ultrasnow. However the baseband remained unchanged to 5.16.02. My iphone 3gs however never was upgraded to the ipad baseband.
this tutorial is for you if you already have baseband 6.15.00 installed. If you need to install the iPad baseband (breaks your GPS), you should use redsn0w
Works for me too!!
Thanks.
thank u soo much for this post. i spent soo much time trying to figure out my phone. it was in recovery loop. my friend got it on and jailbroke and gave it back and i could not call. i followed your steps and as soon as ultrasnow downloaded i got service. thank u so much. god bless.
I have a mac, does snowbreeze work on macs? what is the alternative?
pawnge tool
can i also downgrade from ios5 with this method?
only the iOS
looks like this is not working anymore, I can't get out of tethered JB 4.1
When I run the restore it just hang on Preparing iphone for restore. Any alternative idea? Thank you
Thank you so much buddy, I though it was not working because I got stuck on preparing iphone for restore when I accidentally press the power button the process went on. Yahoo!
I just wanted to post a thank you. I was stuck for days with my 3gs on dfu loop. I loaded tinyumbrella with 4.1 shsh, and restored through itunes with 4.1. NOTHING else worked, only that. THANK YOU!
you are the best so far out here.
many many thanks.
well done
thanks from Greece
tsouk11
I AM TRYING TO UNLOCK MY IPHONE 3GS BB 6.15.0 TO WORK HERE IN gREECE.
I DID EVERYTHING U SAID AND IT WORKS TILL IT COMES TO THE POINT TO SEARCH FOR CARRIER I GET THE ERROR "UNABLE TO LOAD NETWORK LIST".
WHAT CAN I DO TO FIX THAT.
THANKS IN ADVANCE.
I too am having this issue, at first I upgraded my 3GS to iOS 5.0.1 forgetting that I did the BB update, then it wouldn't get past the setup activation screen and so I had to revert to older firmware versions. I tried 4.1, unable to load network list I then updated to 4.2.1, unable to load network list. Please has anyone got a fixable solution for this?
Hi, everything moves along well until iTtunes gives me an error #3194. Any idea why?