Downgrade iPhone Baseband 05.12.01 to 04.26.08

With the release of iPhone firmware 3.1.3 many of the iPhone unlockers lost their iPhone unlock capability because iPhone OS 3.1.3 updates baseband to 05.12.01 which is not unlockable ATM.

In this iPhone guide you’ll learn how to downgrade iPhone Baseband 05.12.01 to 04.26.08 so that you may regain your unlock and use any Carrier SIM on your iPhone. These instruction are applicable only if you fulfill the criteria mentioned below:

NOTE: A large number of iPhone 3G and all iPhone 3GS are not supported by the Fuzzyband 3.1.3. If you fall in this category and have updated baseband 05.12.011 then wait for the Dev-Team to come up with an unlock for Baseband 05.12.01. An exploit to unlock baseband 05.12.01 has been found but converting it to a working unlock may take weeks or even months.

If you meet the above mentioned criteria then you can easily downgrade iPhone baseband 05.12.01 to 04.26.08 and then unlock iPhone OS 3.1.3 using UltraSn0w. To downgrade iPhone 3G baseband 05.12.01 you need to use latest version of Fuzzyband available in Cydia. Follow the step-by-step instructions below to downgrade iPhone Baseband 05.12.01:

Downgrade iPhone Baseband 05.12.01 to 04.26.08

Step 1

Go to Cydia and search for FuzzyBand and install it.

downgrade baseband 05.12.01 fuzzybanddowngrade baseband 05.12.01 fuzzyband

Step 2

Now open the FuzzyBand app installed on your iPhone springboard.

FuzzyBand will display the current Bootloader, Baseband and firmware version of your iPhone. If you fulfill the downgrade Criteria, Tap the downgrade button to downgrade Baseband 05.12.01 to 04.26.08.

downgrade baseband 05.12.01 fuzzybanddowngrade baseband 05.12.01 fuzzyband

Step 3

Once your iPhone baseband is downgraded to 04.26.08 now you can easily unlock iPhone 3GS using the guide linked below:

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For iPhone OS 3.1.2:

9 comments… add one
Mauricio February 16, 2010, 1:19 am

Aguardando novidades… pra quem tem Modelo MC… infelizmente não funciona… MC131BZ… (testado)

vesh February 16, 2010, 9:34 pm

how can i downgrade iPhone baseband 05.12.01 to 04.26.08? when i update 3.1.3(7E18) version in my iphone via itunes, the cyndia program is removed automatically. and my phone is lock. please how can i get the cyndia again in my iphone and unlock my iphone.

kriZ February 17, 2010, 3:00 am

http://img186.imageshack.us/img186/2784/img0024o.png
oh noes! aint got cydia? it just disappeared.

YoungSokattra February 26, 2010, 7:38 am

please help me! how to downgrade bootloader version from 05.09 to 05.08. I think we we should have solution for this. Someone said it hardware issue so we can’t downgrade, if we try to do this, our phone will be killed.

Any good idea about this please share.

Thanks

iPhoneHeat February 26, 2010, 10:03 pm

not possible..

hacker March 14, 2010, 11:49 pm

No need ultrasn0w or any unlock tool if u are base-band 04.26.08 just download pwnagetool 3.1.5 and fw-3.1.3 make costom restore expert mode. don’t go to DFU mode open itunes then press (mac alt) or (windows option) key click restore. Then find a file iPhone1,2_3.1.3_7E18_Custom_Restore.ipsw click it
Thats it
Caio

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