Can I upgrade to 4.2.1? Help!

[redsox786]

Currently have a 3GS with 4.1 and 05.13.04 BB. Can I upgrade to the latest firmware 4.2.1 and still have it unlocked? I need both a jailbreak and unlock for my phone as I am on T-Mobile. I also have a Mac and PC. Thanks!

 

[Myzhi]

If you want to update and keep your baseband = unlock, always updated using a custom firmware file (one that keeps your current baseband). Is 3GS old or new bootrom? If old, you can update and have untethered JB. If new, wait until an untethered custom JB update becomes available for it before updating.

 

[mrat93]

If you want to update and keep your baseband = unlock, always updated using a custom firmware file (one that keeps your current baseband). Is 3GS old or new bootrom? If old, you can update and have untethered JB. If new, wait until an untethered custom JB update becomes available for it before updating.

That untethered jailbreak came out yesterday for all 4.2.1 devices.

OP, to preserve the baseband, use Pwnagetool 4.1.3. If you have the old bootrom, it should be straightforward. If you have the new bootrom, use This guide.

 

[redsox786]

I have a 3GS with the new bootroom. mrat93, if I follow that guide and use Pwnagetool 4.1.3, I will be creating a 4.2.1 Custom Firmware while still preserving my baseband. Is this correct? I can then unlock it?

 

[mrat93]

I have a 3GS with the new bootroom. mrat93, if I follow that guide and use Pwnagetool 4.1.3, I will be creating a 4.2.1 Custom Firmware while still preserving my baseband. Is this correct? I can then unlock it?

If you're on 4.1 and you use the above guide, you will create a custom 4.2.1 firmware file and preserve your baseband. I did this a couple hours ago and it worked fine.

 

[KentuckyHouse]

What about someone on a 3GS, new bootrom, but on Windows? I can't use pwnage tool and I've been wondering how I should go about updating to 4.2.1 and still keep my 05.13.04 baseband? Can someone point me to a tutorial for Windows users?

Oh, and I'm on a 3GS, 4.0 jailbroken with jailbreakme, and as previously stated new bootrom and 05.13.04 baseband.

 

[klamse25]

If you want to update and keep your baseband = unlock, always updated using a custom firmware file (one that keeps your current baseband). Is 3GS old or new bootrom? If old, you can update and have untethered JB. If new, wait until an untethered custom JB update becomes available for it before updating.

I thought for sure that the new TU update supports upgrading, while perserving BB.
Correct me if I'm wrong.

 

[redsox786]

Has anyone else confirmed this method? I want to be sure before doing anything, because I really need my 3GS to be unlocked.

EDIT:

I just did exactly as the guide, made the custom 4.2.1 firmware, but I don't see Cydia installed! I can confirm that it is 4.2.1 installed and the baseband remains at 05.13.04. How can I get Cydia back? Help!!!