I've successfully replaced my new Iphone FW ver 1.1.1 to 1.0.2.

// To do that:
//1. you need to download 1.0.2 FW ipsw file and have it secured on your HDD.
//(hxxp://appldnld.apple.com.edgesuite.net/content.info.apple.com/iPhone/061-3823.20070821.vormd/iPhone1,1_1.0.2_1C28_Restore.ipsw)
//2. Put you Iphone into restore mode
//3. Plug USB
//4. Open Itunes
//5. Press and hold SHIFT while selecting restore button it will open a file window //where you must select previously downloaded IPSW file.
//6. DO NOT DISCONNECT until itunes finished downgrade

Unfortunately I still can not Jailbrake it.

UPDATE
I did it with brand new 8GB Iphone model A1203

YOU DONT need to activate to restore. You just need to run Iphone in a restore mode and than plug it to Itunes. This will bring up an error message saying that you need to activate before but you can skip it and go to a selective restore by pressing and holding SHIFT

I did it with Itunes 7.4.1.2; WinXPP.

That won't work. You will receive an error on your phone during the downgrade process

??????????????

I thought this method does NOT work

Do you mean you UPGRADED from 1.0.1 to 1.0.2??????

if u successfully downgraded why do u mention

to admins:
PLZ delete if useless.

this will get locked just like the other one...if u sucessfully downgraded u would be able to jail break...if u can't jailbreak...thats because i didnt downgrade..

Also, how did you get past the activation screen. I too have a FW 1.1.1 but each time i connect to i tunes (or turn the phone on) it requests for activation.

people posting this stupid **** without any proof should be banned

I did it. I still cant jailbrake.

YOU DONT need to activate to restore. You just need to run Iphone in a restore mode and than plug it to Itunes. This will bring up an error message saying that you need to activate before but you can skip it and go to a selective restore by pressing and holding SHIFT

I did it with Itunes 7.4.1.2; WinXPP.

Originally Posted by drsub

if u successfully downgraded why do u mention

to admins:
PLZ delete if useless.

this will get locked just like the other one...if u sucessfully downgraded u would be able to jail break...if u can't jailbreak...thats because i didnt downgrade..

That can also happen because of some other things done by apple except FW fix

Originally Posted by NeAmico

I did it. I still cant jailbrake.

YOU DONT need to activate to restore. You just need to run Iphone in a restore mode and than plug it to Itunes. This will bring up an error message saying that you need to activate before but you can skip it and go to a selective restore by pressing and holding SHIFT

I did it with Itunes 7.4.1.2; WinXPP.

How do you know the downgrade worked if you can't activate the iPhone???
My guess is: you still have FW 1.1.1.

Originally Posted by NeAmico

That can also happen because of some other things done by apple except FW fix

Any changes made by apple would be because of the 1.1.1 firmware. That is why you can't jailbreak the phone and that is why you didn't downgrade