Baseband Downgrade problem (5.1.1 to 4.3.3) - GSM-Forum

aseer1 · 06-20-2012, 13:56

Hello there guys,

I was using 4.3.3 before I decided to upgrade to 5.1.1. I was planning to use SAM unlock but unfortunately, I noticed that I had to backup "cookies" (or whatever it is) to use it on 5.1.1 after I upgraded :/. Since I don't have any backups for that, I decided to go back 4.3.3 (I couldn't upgrade to 5.0.1 because iTunes always giving an error and of course I don't have shsh for 5.0.1). I turned back to 4.3.3 but I noticed that my baseband is still 04.12.01. Isn't it supposed to downgrade to original 4.3.3 baseband, which is 4.10.01 ? I even tried to make a cfw with sn0wbreeze but its still has the same baseband (i might not using sn0wbreeze as it supposed to be, so I'm open for enlightments).

Because of this, I can't use my Gevey solution. I have all iOS 4.x shsh's but none 5.x except 5.1.1 :/

Foot note: I saw that AT&T started to unlock off-contract iPhone's and mine is too. I tried to contact with AT&T through their sites but they require you to create an account and link it to your service which I don't have any document or information about my AT&T credentials. Is there any way to pass through that authentication and ask for them to unlock my phone ?

Thanks for your time&hel

marlmx · 06-20-2012, 16:11

Well i guess you want to downgrade your baseband beacuse you want to unlock?

When you do an upgrade of iOS wich cames with new baseband, and then you do the downgrade to other iOS the new basebands stays (this means baseband downgrade is not possible). this is possible only by doing a custom firmware with sn0wbreeze for example but *BEFORE* using the original firmware.

Anyway the baseband you have 5.12.01 is possible to unlock with jailbreak+ultrasn0w, but i not sure if the 5.1.1 iOS upgrade to other baseband?

Also you can upgrade to 6.15 bb and then downgrade to a 5.13 bb so you can unlock, with new redsn0w but you need to check your serial number beacuse in some models this process bricks the phone. If you have an iPhone3GS and if digits 3-5 of its Serial Number are 134 or later (xx134…), then you should NOT try to install the 06.15 baseband on your 3GS

Marlmx.-

mrfixit · 06-20-2012, 16:25

according to his description he talking about iphone 4,
he dont have bb 5.12.01 he have 4.12.01 and no unlock possible with this except factory unlock, cost about 100usd and 3 days waiting. no bb downgrade possible for iphone 4 yet.
sam unlock finished months ago, so too late for this.

06-20-2012, 13:56	#1 (permalink)
aseer1 Freak Poster Join Date: Jun 2006 Location: iran Posts: 432 Member: 303488 Status: Offline Thanks Meter: 208	Baseband Downgrade problem (5.1.1 to 4.3.3) Hello there guys, I was using 4.3.3 before I decided to upgrade to 5.1.1. I was planning to use SAM unlock but unfortunately, I noticed that I had to backup "cookies" (or whatever it is) to use it on 5.1.1 after I upgraded :/. Since I don't have any backups for that, I decided to go back 4.3.3 (I couldn't upgrade to 5.0.1 because iTunes always giving an error and of course I don't have shsh for 5.0.1). I turned back to 4.3.3 but I noticed that my baseband is still 04.12.01. Isn't it supposed to downgrade to original 4.3.3 baseband, which is 4.10.01 ? I even tried to make a cfw with sn0wbreeze but its still has the same baseband (i might not using sn0wbreeze as it supposed to be, so I'm open for enlightments). Because of this, I can't use my Gevey solution. I have all iOS 4.x shsh's but none 5.x except 5.1.1 :/ Foot note: I saw that AT&T started to unlock off-contract iPhone's and mine is too. I tried to contact with AT&T through their sites but they require you to create an account and link it to your service which I don't have any document or information about my AT&T credentials. Is there any way to pass through that authentication and ask for them to unlock my phone ? Thanks for your time&hel

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06-20-2012, 16:11	#2 (permalink)
marlmx Junior Member Join Date: Feb 2011 Posts: 4 Member: 1517744 Status: Offline Thanks Meter: 0	Well i guess you want to downgrade your baseband beacuse you want to unlock? When you do an upgrade of iOS wich cames with new baseband, and then you do the downgrade to other iOS the new basebands stays (this means baseband downgrade is not possible). this is possible only by doing a custom firmware with sn0wbreeze for example but BEFORE using the original firmware. Anyway the baseband you have 5.12.01 is possible to unlock with jailbreak+ultrasn0w, but i not sure if the 5.1.1 iOS upgrade to other baseband? Also you can upgrade to 6.15 bb and then downgrade to a 5.13 bb so you can unlock, with new redsn0w but you need to check your serial number beacuse in some models this process bricks the phone. If you have an iPhone3GS and if digits 3-5 of its Serial Number are 134 or later (xx134…), then you should NOT try to install the 06.15 baseband on your 3GS Marlmx.-

06-20-2012, 16:25	#3 (permalink)
mrfixit No Life Poster Join Date: Apr 2004 Location: MOON Posts: 5,858 Member: 60899 Status: Offline Thanks Meter: 792	according to his description he talking about iphone 4, he dont have bb 5.12.01 he have 4.12.01 and no unlock possible with this except factory unlock, cost about 100usd and 3 days waiting. no bb downgrade possible for iphone 4 yet. sam unlock finished months ago, so too late for this.