Hello iphone experts!
I have an iPhone 3GS, software 3.1.2, firmware 05.11.07, (old bootrom I think iBoot-359.3), currently unlocked. Could I upgrade to 4.2.1 using the same method discussed in this post? I rely on an unlock.
(Perhaps I can update it to 4.3.5 instead of 4.2.1?)
Thanks for your help!
This thread talks about the iPhone 3G, which has a different security model to the 3GS regarding OS upgrades/downgrades/reinstalls. The advice in this thread is not entirely relevant to your situation. The key difference is 3GS enforces an extra check via the SHSH mechanism to limit upgrades/downgrades/reinstalls. In the old bootrom 3GS this check can be bypassed, but for various reasons there aren't straightforward solutions for doing this on iOS 4.1 or higher.
I would suggest you verify which saved SHSH blobs you have and try and reply in a more suitable thread (one that specifically discusses using custom IPSW to preserve baseband in conjunction with a saved SHSH blob on a 3GS)
I have a Iphone 3G 16GB 3.1.3(7E18), Modem Firmware: 05.12.01 Jail broken & Unlocked.
This was the last configuration i had and was fine for me. All the notes on internet around the OS4 and its problems with Iphone 3G ket me off from doing any upgrade. Now when I am looking for information, there are lots and I am throughly confused. I am not a bigtime software expert (though I can manage the upgrade myself). The guidance I am looking for is as follows:
1) is it worth upgrading from 3.1.3(7E18), Modem Firmware: 05.12.01 Jail broken & Unlocked? (problems for me is, most apps now indicate need for OS4 or above. What is an iphone without apps to use)
2) if its worth what should be level upto which I need to upgrade (4.1/4.2 etc.. confused)?
3) I need to have the phone unlocked else its of no use to me. I don't have the original SIM card for registering. :(
My system is windows XP Professinal V2002, service pack 3.
Request team to guide me and/or direct me to the DIY site.
Thanks in advance
You must use Pwnagetool / sn0wbreeze custom IPSW to prevent baseband update (that way you can still unlock)
4.2.1 is the most stable/fastest but al iOS 4.x are slower than 3.1.3 on an iPhone 3G
This is a topic that has been explained in detail before. iClarified has guides that explain how to use Pwnagetool to achieve this. Search around on hackint0sh for detailed threads, ask if that thread is appropriate before you try it.
Do NOT ever load an original IPSW as you will lose your baseband and thus ability to unlock.