How to Downgrade Your iPhone 3GS, 3G Baseband for Unlock

[Sitlay]

These are instructions on how to downgrade your iPhone 3GS or iPhone 3G's baseband from the iPad's 06.15 baseband to 05.13.04 using RedSn0w.

Typically you’d have the 06.15 baseband if you unlock with ultrasn0w but updated your iPhone baseband past 05.13.04. With this new capability, you can now downgrade specifically from 06.15 to 05.13.04 (even if you never had 05.13.04 on that device before). This gives you the best of both worlds: ultrasn0w unlock compatibility and a normal iPhone baseband with full GPS and the ability to use stock IPSWs again.

Step One
Create a new folder on your desktop called Pwnage.

In the folder place the current firmware of your device and the latest version of RedSn0w.

Extract the RedSn0w zip file by double clicking it.


Step Two
Launch the redsn0w application from the redsn0w folder we extracted earlier. You can do this by right clicking the executable and selecting Run as Administrator contextual menu.




Step Three
Once RedSn0w opens click the Extras button.


Step Four
Choose Select IPSW from the Extras menu.


Step Five
Navigate to the Pwnage folder on your desktop, choose the firmware ipsw we downloaded earlier, and click Open.


Click OK to confirm your selection.


Tell RedSn0w whether you have a newer or older model iPhone 3GS.


Step Six
Press Back to get back to the main menu then click the Jailbreak button.


Step Seven
RedSn0w will now prepare the jailbreak data.


Step Eight
Check the Downgrade from iPad baseband checkbox, disable Cydia if you already have it installed, and click Next proceed through the normal DFU ramdisk steps.


Step Nine
Plug your iPhone into the computer and make sure its OFF then click the Next button


Step Ten
RedSn0w will now guide you through the steps to get into DFU mode. You can find more help with DFU mode here.


Hold down both the Home button and the Power button for 10 seconds.


Release the Power button and continue holding the Home button until RedSn0w detects the device.


Step Eleven
Your iPhone will now be exploited with limera1n and reboot


Step Twelve
Your iPhone will now be rebooted again and RedSn0w will begin uploading the new RAM Disk and Kernel.


Step Thirteen
RedSn0w will now inform you that its work is done. The rest of this process will take place on your device.


Step Fourteen
After showing some scrolling text, your iPhone will display the pwnapple icon and say Flashing Baseband. THIS STEP TAKES A VERY LONG TIME to complete and there won’t be any feedback while its running. Please just let it be for the next 3-8 minutes! When the ramdisk has done its job it will reboot the phone on its own.


Step Fifteen
Once the phone has rebooted you will be on the 05.13.04 baseband.

***A big thanks to the iPhone Dev-Team for making this possible!

[centurion689]

For some reason after downgrading my baseband none of my cydia apps are working. They are still on the screen but they don't work. I also have no service. Got any idea how to fix this? Perhaps reinstalling Cydia?

EDIT: Just had to reinstall mobile substrate and now everything is working beautifully.

Thanks for the guide.

[madusmacus]

Thanks for the info and pictures :¬)

[IzTiz]

Well doesn't work for me, still on 6.15.00

[Sitlay]

Originally Posted by IzTiz

Well doesn't work for me, still on 6.15.00

give it an other chance it wouldn't hurt you
Just try again dear

[_anntot_]

it doesnt work for me. and worst, my unlock is now not working. i have tried reinstalling all of my cydia apps and still cant make my unlock work. help!!!!


i was able to unlock my phone again...here's what i did:

1. go to cydia>packages>mobile substrate>modify>reinstall but instead of confirming, i clicked on "continue queuing"
2. back to packages>ultrasnow>modify> reinstall>confirm
this will reinstall both apps and succesfully unlock ur phone again

seems like the downgrade of the 6.15.00 still got issues. ill just wait and try some more of the solutions to be posted.

[IzTiz]

Originally Posted by Sitlay

give it an other chance it wouldn't hurt you
Just try again dear

Tried 10 times and still on 6.15.00. I thinks the process failed somewhere.

Sorry for my english.

[rjside]

theres no error while im downgrading but after all the Process im jailbroken, but im still on 06.15 baseband,, any suggestions?

[mlira]

hope you cold help me, i just have bought an iphone 3gs and its jailbreak 4.1, but i want to upgrade to 5.1.1, reading forums i found that some guy had made jailbreak 5.1.1 have a "no signal" problem, if i downgrade my baseband, can i make jailbreak 5.1.1 without the no signal problem?

the info of my iphone are:
línea: telcel
version: 4.1 8b117
carrier: telcel 8.0
model: mc132e
sn: 84014qvj3nq
baseband: 06.15.00


Thank you

[RYU81]

after process without any error still on 06.15 baseband

[_anntot_]

Originally Posted by mlira

hope you cold help me, i just have bought an iphone 3gs and its jailbreak 4.1, but i want to upgrade to 5.1.1, reading forums i found that some guy had made jailbreak 5.1.1 have a "no signal" problem, if i downgrade my baseband, can i make jailbreak 5.1.1 without the no signal problem?

the info of my iphone are:
línea: telcel
version: 4.1 8b117
carrier: telcel 8.0
model: mc132e
sn: 84014qvj3nq
baseband: 06.15.00


Thank you

i think my post above will andswer your issue on the no signal problem.

[Sky_Knight]

After you successfully downgrade, it must show in the About section of settings that you are on Baseband 05.13.04 right ?

---------- EDIT ----------

Old bootrom 3GS, 4.3.3 and tried this process twice, the steps were successful as it was shown in the guide but it is still at 06.15.00 and good thing, my unlock is gone and its not coming back no matter how many times i reinstall ultrasnow and mobilesubstrate...

[Sky_Knight]

Reinstalling iPad Baseband from RedSnow helped fix the problem.

[nymph187]

is it working on baseband 5.16.05?

[l8ter]

As far as i know it is for downgrading from the iPad baseband wich is 06.15.00 .So i would assume no that doesn't work on that baseband you asked for .