I've tried everything and I always get this error can anyone help ?

The solution to this problem:

Open up the terminal.
go to '~/iTunes/'
make a new directory 'mkdir "Device Support" '

That'll fix the problem. Start over and you'll be fine. (Ignore the single quotes BTW, if it wasn't obvious.
Alternatively, I see no reason why this needs to be done in the terminal. You can probably do it just using the finder.

When you get the error, you are most likely not in DFU mode.

Lots think they are because iTunes says you are and the screen shows an iTunes logo with the USB cable. That's not DFU mode.

So how to enter DFU mode:
When the iphone is on => press both the power and home button. After 7 seconds (screen is black then) release the power button and keep the home button in till iTunes detects your iphone.
Important => Your iphone must be connected to iTunes before you follow the above steps. Connecting your iphone will kick it in restore mode.
In DFU mode, the screen is totaly black and the iphone apears to be off.

Hope this helps....

Dont start in dfu mode, follow the timed prompts in Pwnage to get into dfu mode.

Originally Posted by Dhalilahma

Dont start in dfu mode, follow the timed prompts in Pwnage to get into dfu mode.

You are right, sure. i had an issue once or twice not getting into DFU mode with pwnage Tool 2.0.1. Probably my fault - bad timing. So I shut down the iPhone then quit Pwnage Tool, start iTunes and then put the iPhone into DFU manually as mentioned above. Restore to custom fw works like a charm then aswell.

volkspost

Hi, Having recently purchased a used iPhone G4, I'm a novice to the whole Pwnage Unlock/Jailbreak thing, but happily for me I did it— finally! But man, it was tough! I had to try at least ten times.

I followed the "Pwnage 2.0 Guide" (http://sleepers.net/news/guides/pwnage-20-guide/) which did helped. BUT, left out was one crucial step (at least for novices like me). BEFORE one even opens Pwnage 2.0, one needs to put their iPhone into "DFU mode or all the other steps won't work (at least that was the case for me).

Even getting into that before the whole "Pwnage 2.0' experience up front was tough, and I really don't remember which of a number of attempts finally got me in to it in the "right way" to finally "Pwn" my iPhone G4.

ALSO, critical to note at the end of the Pwnage 2.0 process (and it is a process!) when one is in iTunes to do the final Pwned Restore, "Option-Restore" means hold down the "Option" key when clicking Restore, to get to the Pwned custom firmware file created earlier on your Desktop that does the Pwning otherwise you'll just get a plain vanilla Apple restore with no Pwnage Unlock/Jailbreak done at all. That happen to me before I figure that key item out. X <

Simple, right? Yeah, right! GOOD LUCK!

P.S. on how to get into DFU mode

Step 1. Turn off your iPhone by holding the top power button, then sliding the red button that pops up to the right.

Step 2. Hold down the power and home button.

Step 3. When you see the Apple logo, release the power button but continue holding the home button down.

Step 4. Open iTunes and wait for it to tell you that its in restore mode.

Step 5. Close iTunes and THEN open Pwnage 2.0 and follow the step-by-step instructions it gives you

Originally Posted by SirCastor

The solution to this problem:

Open up the terminal.
go to '~/iTunes/'
make a new directory 'mkdir "Device Support" '

That'll fix the problem. Start over and you'll be fine. (Ignore the single quotes BTW, if it wasn't obvious.
Alternatively, I see no reason why this needs to be done in the terminal. You can probably do it just using the finder.

i could not jailbreak my iphone 3G, it always gave me the message could not enter the DFU mode, i do have a macbook Pro new version and also the itunes 8, i tried also to go to terminal and searched for '~/iTunes/', but it could not be found, please guide me to jailbreak my iphone 3G successfully.