iPhone 3GS help unlocking

[King Royalty]

I have an iPhone 3GS that was on 5.0.1 and finally got it to downgrade to 4.1, the firmware is on 05.16.05, I would like to know what are the final steps to get this thing unlocked and what version of redsn0w I would need to use, also would like to know how am I able to tell if I am running on a custom os because i downloaded 4.1 custom but not sure if its the one I have installed, thanks!

Edit: Also its running on a newer bootrom if that makes a difference.

[i.Annie]

If you don't mind possible break of GPS and only being able to restore to custom firmwares on 4.2.1 and higher, you can unlock by upgrading the baseband to 6.15.00 (iPad baseband flash). You can do so on 4.1 with Redsn0w and the appropriate version for 4.2.1/4.1. There are no other option to unlock your device with the baseband you have. And you cannot downgrade the baseband.

After installing the iPad bb on your iPhone, and jailbreaking, you can install Ultrasn0w to unlock. Just be sure to install the iPad bb separately from installing Cydia, don't do both at the same time.

[rmsmillertime]

Ok - so first of all, are you locked to a US carrier (ATT)? If so, Ultrasnow is the software unlock if you want to use a different carrier than you are locked to. Problem is that bb 5.16.05 is not supported by Ultrasnow. In order to unlock, you would have to flash with the ipad baseband 6.15, which is supported by Ultrasnow. You will lose GPS, but retain triangulation. This is the only way to unlock an ATT phone. If your phone is from outside the US, you might be able to get your carrier to unlock your iphone for a fee.

There are many threads on the process for flashing the ipad baseband and what you should consider before doing so.
As far as bootrom, no difference at 4.1
FYI, Apple is still "signing" 4.1 firmware.

[avalon 2406]

I have an iPhone 3GS that was on 5.0.1 and finally got it to downgrade to 4.1, the firmware is on 05.16.05, I would like to know what are the final steps to get this thing unlocked and what version of redsn0w I would need to use, also would like to know how am I able to tell if I am running on a custom os because i downloaded 4.1 custom but not sure if its the one I have installed, thanks!

Edit: Also its running on a newer bootrom if that makes a difference.

King Royalty

How did you get down from 5.0.1 to 4.1? i have found this totally impossible? I am also using firmware 05.16.05, and have tried everything for a week now going totally nuts here and really hope someone can help me, here is what i have tried so far....

Downgrading (I tunes) will not accept the build
Ultrasnow
Redsnow
Tiny Umbrella
Greenpoison
Limerain
Snowbreeze
Installing I pad baseband.

[i.Annie]

4.1 is still signed for 3GS. The fw version can be downgraded bc of that but the baseband can't be downgraded for unlocking.

5.16.05 is the baseband. That's what determines unlockability. You cannot downgrade the baseband unless it's an iPhone 3G with bootloader 5.8.

[avalon 2406]

thanks for the reply Annie, but can i not change my baseband then? I just cannot unlock this phone, and have an i pad... so am not new to unlocking, is there anything you can suggest to help me? as you can see what i have already been trying? above

[i.Annie]

Correct, you can't downgrade the bb. If you want to unlock for another carrier, you must upgrade the iPhone's baseband to the iPad bb.

If you are outside the US, try asking your carrier for a factory unlock.

[King Royalty]

If you don't mind possible break of GPS and only being able to restore to custom firmwares on 4.2.1 and higher, you can unlock by upgrading the baseband to 6.15.00 (iPad baseband flash). You can do so on 4.1 with Redsn0w and the appropriate version for 4.2.1/4.1. There are no other option to unlock your device with the baseband you have. And you cannot downgrade the baseband.

After installing the iPad bb on your iPhone, and jailbreaking, you can install Ultrasn0w to unlock. Just be sure to install the iPad bb separately from installing Cydia, don't do both at the same time.

I have cydia already so now I just install the ipad baseband then the custom firmware? or vice versa? also my serial is xx130x would the ipad baseband work on that?

[i.Annie]

You don't use a custom fw. You're already jailbroken. Just install the iPad bb.

[King Royalty]

You don't use a custom fw. You're already jailbroken. Just install the iPad bb.

wouldnt i ruin it by updating the baseband to 6.15 since my serial is xx130x?

[i.Annie]

Your serial number doesn't have anything to do with the baseband and unlocking.

Your only option of unlocking is if you upgrade the bb which can break your GPS and will restrict you from using stock fw on 4.2.1 and higher.

[b0bab0i]

Your serial number doesn't have anything to do with the baseband and unlocking.

Your only option of unlocking is if you upgrade the bb which can break your GPS and will restrict you from using stock fw on 4.2.1 and higher.

Your serial does matter, Apple changed hardware on newer 3GS, so if you tried installing iPad baseband, it would brick the phone.

Anything produced past August 2011 (135 i believe) , phone will be bricked if you try changing baseband.

[i.Annie]

Thought that theory was disproved. Perhaps I'm wrong. Thanks for the clarification.