Pls backup your ECID certificate to Cydia, this is very important.. Don't upgrade to 3.1 ELSE u will NEVER able to JB again.... JB with 3.0 or 3.01 should be fine.. Pls refer to page 1 of this thread for JB to 3.01..

This post has been edited by sugen: Sep 21 2009, 03:57 PM

How to unlock my iPhone 2G without jailbreaking? I want to use the original firmware 3.1OS

I m a newbie here ..anyway, ytd i have upgraded to OS 3.1 for my iphone 3GS ...which i think there is abit of problem on the new OS
i wanted to downgrade back to 3.0.1 ?? how can i do that ??

need some guide here ..thank you

if you upgraded from itunes, then I don't think that's possible anymore bro.
Btw, theres a thread here somewhere that answers your question.

@Kernkraft400
That's not possible as iPhone 2G will always need to be jailbroken. Why? Because it need to be "hacktivated". The unlocking part, if you already unlock the iPhone 2G baseband, it will still be unlock even if you upgrade the firmware as Apple did not update the baseband anymore.

I have jailbroken my iPhone on 3.0.1, so all i have to do is just download the original firmware from apple, and upgrade. And the phone will still be unlocked? Is that what you are trying to say?

NO WAY for you to downgrade & u will never able to Jailbreak your iphone 3GS again... All you have to do is say goodbye to JB..

aih, i should not upgrade at the 1st place ...damn

Yes, even if you downloaded the iPhone OS v3.01 file you can never restore back because Apple has stopped signing 3.01. Also JB won't work at least for now because the modem firmware has been updated and patched a vulnerability/hole required for the current JB method. A new JB method is on the way. No one knows when but it'll be here when it is here.

hmn... Not able to JB on 3GS is NOT because of the modem firmware has been updated & patched the vulnerability/hole required for the current JB method... You are wrong in this point..

It is because of 2 thing..

1.) The chips
The specific number they have chosen is the device's ECID, or "unique-chip-id", a number that all devices have so far had, although we haven't seen any previous use for it.

2.) The signature server
Of course, new hardware comes every year, and Apple decided to strike hard with the new iPhone 3G[S]. Rather than just throw in new local protections, Apple decided that every restore of the device would be verified as being valid and safe by Apple itself.

To do this, during the restore process, users see "Verifying restore with Apple...", during which time a challenge/response protocol is used between the iPhone and Apple: a "partial digest" of the firmware files being used is sent to a server, which can then decide to sign off on the result... or not.

Not only does this allow Apple to keep custom firmwares from getting loaded onto the device, but it also allows them to recall existing firmwares by keeping people from restoring to them in the future. To do this they simply would refuse to ever sign, for example, iPhoneOS 3.0 again.

However, to make this model secure, one must verify that their system is not subject to a simple "replay attack": where one just stores a copy of Apple's sign off and then returns it at a later point. This is a "beginner's attack", and one that is easily mitigated by any of a number of strategies.

This post has been edited by sugen: Sep 21 2009, 05:09 PM

Try to download the 3.0.1 firmware. the IPSW file
open up itunes, under ur iphone, hold shift then click restore.
select your 3.0.1 IPSW restore file and do the restoration. and it should work.

This post has been edited by rip_code: Sep 21 2009, 05:47 PM

@sugen
very cool... complete explanation.

@rip_code
Apparently Apple is enforcing the "you cannot downgrade your iPhone" feature, and they're starting with the 3G [S]. I've tried with 2 different phones already, it usually fails at the "Verifying with Apple" section

Oh ok. Apparently I didn't have 3GS yet. Using my old skool 2G iPhone. Thanks for the clarification

have u try modify the host file???it "cheat" the itunes to go to diff server...if i not wrong..

Won't work if you did not backup the ECID in the first place.

yes u can cheat the itune to redirect to saurik server..... but if u didn't upload d ECID n SHSH into saurik server in the first place.... then redirect to saurik server won't work

When i restore my iphone to 3.0 version
It prompt out this message
" This iphone could not be restore.It's not eligible for the request builded"
btw i'm running 3.0.1

so with the 3.0 can jb is it? NEVER try to update 3.1 first before the JB come out? am i correct? but need to backup your ECID certificate to Cydia..

This post has been edited by tabs: Sep 21 2009, 07:47 PM

UPDATE: Updated my 2G to OS3.1 using my mac, but cydia installer is not installed.

This post has been edited by mandyxt: Sep 21 2009, 08:57 PM