How to Downgrade Your iPhone 3GS, 3G Baseband for Unlock (Windows)
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I am on activation screen of 6.1.6 with baseband 6.15.00. The problem with these steps is that my power button doesn't work and so I created a custom IPSW of 5.1.1 as specified in https://www.iclarified.com/entry/index.php?enid=23009 for putting the phone in DFU mode. Will I be able to use that ipsw to put the phone in DFU mode and downgrade it as specified in this tutorial?

You can downgrade only if you have baseband version 06.15.00 (NOT 06.15.05 or like that). If you don't have that you have to first jailbreak with "Install iPad baseband" from redsn0w to get exactly 06.15.00. Then you can jailbreak with "Downgrade from iPad baseband" and then it will work! :)

THANK YOU SIR! ITS WORK I WAS DOWNGRADE MY MODE FIRMWARE 6.15.0 TO 5.14 Thank you!

Whatever I do I am unable to downgrade the baseband for my iPhone 3GS running iOS 5.1.1 from 6.15.00. Have tried all steps on all forums. Its been 4 days I have been trying continuously....

for ios 6.1.6 you must use the ios 6.0 ipsw to get redsnow to read the ipsw. this worked for me hope it works for someone else !!

me too gjg erroe

i did a full restore

Help pls... Error! Please reboot the device into normal operating mode, then perform a clean "slide to power off-

what ipsw to use when i'm on ios 6.1.6 now?

what ipsw to use when i'm on ios 6.1.6 now?

My ophone struck on Rebooting...

Redsn0w is not supporting "iPhone2,1_5.1.1_9B206_Restore". It says this version of Redsn0w doesn't support this. have iphone 3gs iOS 6.1.6 which i recently jailbreak but after the jailbreak it shows "no service" and in ICCID shows No SIM..Please help.. should i download some other version of firmware.?

Just Install Ultrasn0w from cydia for your unlocking problems

i have to fix the no wifi problem while unlocking iphone 3gs

For people having trouble unlocking their AT&T devices, you can check out attiphoneunlocking, they can unlock all AT&T device up to date

is these error fixed??? unable to downgrade baseband due to error - dyld: code signature for shared cache failed with errno=7

it replied me exploit failed.now what should i do.....?

Hey I'm on a iphone 3G with 3.1.3 with ipad baseband. What should i do. Can't install 4.2.1 to do this process

My iphone 3gs have problem with "no services" error. I have done step by step but can't still downgrade from 6.15 to 5.13. Its information: Version 5.1.1 (9B206) Model MC131B Serial 8700485Z3NP IMEI 012154000135252 ICCID NoSIm Firmware 06.15.00 When I check, my iphone is new boot room. Please help, Thanks,

Hello, This thing is stuck on Waiting for Rebooting...can anybody tell me how to get it fix? or maybe I should downgrade from firmware 6.1.3 to 6.1.2 and I would like to have the instruction how to do it. Thanks!

I had the same problem than you (with an iPhone 3GS, ios 6.1.3) and here is how I fixed it : before starting the downgrading process, you click on "Extras", then "Select IPSW" and choose the ios 6.0, even though you're in 6.1.3. Its because Redsn0w doesnt support the ios 6.1.3 so you're gonna trick it into believing that you're in 6.0. Once you've done that, (and you need to specifiy wether you have the old or the new bootroom), you can start downgrading your baseband as explained in this tutorial. And everytime you want to use redsn0w (for booting, or anything else), you have to do the same thing again : selecting the 6.0 ipsw. And it won't be stuck on "waiting for rebooting" anymore !

which version of redsnow?

Thanks for your help, but Still no luck it just hang when it's loading the jailbreak it couldn't even get to the pineapple part. Don't know what else to do with this phone it's very frustrating.

unable to downgrade baseband due to error - dyld: code signature for shared cache failed with errno=7

stuck in fetching baseband files........... help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Worked like a charm. Thanks

Hi, i need your help how to upgrade my iphone 3gs baseband 05.13.04 to ios 6.x after following those steps. Can it be unlocked ? Thx

i downgrade my iphone secussfully but it still showing no service

i do all of thes steps. but redsnow stucked in wating for reboot. what i can do now..

for 6.1.3 users.. simply use 6.0 firmware and downgrade from ipad baseband.. and thats it.. then use ultrasn0w.. i have done it many times.. on some 3gs only baseband downgrading works and for some ultrasn0w works..

thank u so much now it is working

i downgrade my i phone secussfull but it still shwing no service

Can you please provide the instruction how to downgrade from 6.1.3 to 6.0? I've been trying to downgrade to 6.1.2 no luck.

Hi guys, Thanks to each one of you for valuable comments and suggestions. For last 2 days I have been searching and trying desperately to bring my 3GS alive. I was trying to upgrade to 6.1. It was not able to search network. So I downgraded it to 5.1.1 (originally I had 5.0.1). But nothing was working. Seeing me sitting whole day over OLD 3GS, my wife threatened to throw my iPhone out of old window :) But finally I was able to crack it :) Following is what I did: - start with iPhone 3GS, 5.0.1 BB 6.15.00. old bootrom. - down load "redsn0w_win_0.9.15b3" and "iPhone2,1_5.1.1_9B206_Restore.ipsw" - Run redsnow with admin access - go to extras-> even more->restore->IPSW. - slect iPhone2,1_5.1.1_9B206_Restore.ipsw. click no on next screen.. - follow as redsnow suggests - iOS 5.1.1 is restored - When the update is completed don't do anything on the iphone. - go back and Click Jailbreak - Click Cydia - Click degrade iPAD Baseband - Click Deactivate - Next and make the procedures of holding the buttons - Wait for the Jailbreak - When the iphone is back again put the SIM CARD again. (it did not work for me, you can check, if it works, great. otherwise continue). - go back and Click Jailbreak- Click Cydia - Next and make the procedures of holding the buttons - Wait for the Jailbreak - When the iphone is back again put the SIM CARD again. And thats it.

ram12xc.. hi i have the same problem with my 3gs. my IOS now is 6.1.3 and i cant get any service Heres my Iphone info's Network: not available Version: 6.1.3 Carrier Not Available ICCID No Sim Modem Firm: 6.15.00 I would like to use the method you posted.. but i down know how to downgrade. Hope for your kind Reply. :)

i successfully unlocked after downgrading base band 6.15 to 5.13 my signal appeared automatically which i earlier installed ultra snow can i upgrade to 6.1.3 with preserving baseband

Thanx alot its worked

Hi I am having the same issue with my 3gs, upgraded to IOS 6.1.3 with baseband 06.15.00. From cydia using ultrasn0w app tried to unlock my carrier, but no luck, reports No service / Searching... I am using 3gs with serial number 8493838X3NR. Can I now able to downgrade? if yes, Please advise. Thnks

correction: IOS = 6.1.3 BaseBand = 6.15

hi there i'm on 6.1.3 with ipad base 6;15 and cant downgrande becous tranfering control to jailbreak… dyld: code signature for shared cache failed with errno=7 this mean shsh ? any way to fix ?

Don't use 6.1.3. Downgrade to 5.1.1 and then downgrade baseband.

Hi I am having the same issue with my 3gs old br I upgraded to 6.1.3 and still have Ipad baseband 6.15.00 and jailbroken with sn0breez all my apps work fine just that I cant get a signal for my carrier I also had it permanently unlocked to avoid this type of stuff. I have tried the tutorials for downgrade to 5.1.1 and cannot conclude the process I keep getting a transfering control to jailbreak... dydl: code signature for shared cache failed with errno=7 I can say I went by the tutorial various times with the same result. Please advise.

i did the same thing but still with 6.15.00

Thanks SOOOO much! It worked a treat :) Safari, email and maps don't work, but that's what chrome is for! Lol Is there a way to fix it by the way?

hey after step ten i got an error SHSH blolbs ! can some 1 help me i'm using iphone 3gs

hey thanks for this greatly clear and simple tutorial ,, before i start doin this process i would like to have you clarify this point for me please ,, now my current version is 6,1.3 ,, is it possible to do that on it or do i need to downgrade it to 6.1.2??

Big Thanks, :D

Thank you iclarified.com. I successfully downgrade from 06.15 to 05.13.04

i'v firmware 4.1(8b117) on baseband 6.15 and i want to upgrade the software but i can't because when i upgrade to ios 5.1.1 i will not have the signal to make calls, so what should i do can any one help me with this?

Hi. I had an iPhone 3g with an ipad baseband 6.15.00 and I want to downgrade to 5.13.04. I had followed every instruction show above. However, after the step Thirteen. my iPhone screen just a blue screen instead of pwnapple. Can someone tell me what's wrong and how to fix it? Thanks

Hi. I had an iPhone 3g with an ipad baseband 6.15.00 and I want to downgrade to 5.13.04. I had followed every instruction show above. However, after the step Thirteen. my iPhone screen just a blue screen instead of pwnapple. Can someone tell me what's wrong and how to fix it? Thanks

I had the same blue screen issue with my 3G and tried the older b2 version of redsn0w and it worked!

Hi to All I have a Iphone 3G, with IOS 4.2.1 and firmware 05.15.04, and need to downgrade for ultrasnow. I need first, before do the downgrade from ipad baseband, I need to the INSTALL IPAD BASEBAND, correct? Thanks in advance

My iphone has ios 6.1.3 (10B329) with baseband 06.15.00. It doesn't have cydia (I use H2O which uses ATT line). Now I was trying to downgrade Baseband, because I wanted to get the IMEI unlock and to switch to Tmobile (gosmart). Can I simply follow the process described above? I am asking this because there are lots of confusing information about ios 6.1.3. (some people say nothing would work once I have ios 6.1.3. installed in my iphone.). thank you for your help.

My i phone 3GS ios 6.1.3 and BB 6.15.00 . Now my phone factory unlocked I just want to change my baseband . How it is possible , can you help me please..