A friend asked me to unlock a 2G 8GB Iphone. Since I had done it with mine and several others 2G and 3Gs I said, EASY... Yeah sure.

I really dont know why, but the phone did not restore from itunes giving the Error 21 and later the 1604, Can Not Restore (it may be that It was unlock and later updated and relocked...) I used the Pwn tool 2.2.5 in Mac at least 20 tries with different firmware versions to no avail. I did follow instructions to the letter trust me....

I thought it was Itunes so I reinstalled at least 3 old versions, from 7.4, 7.5, 7.7 and 8.0.xx No result.

Finally I went to Windows and tried Pwn 2.2.5 same result, Error 21 or Error 1604.

So I decided to use the Quickpwn tool. Per instructions, used the iphone firmware 2.1.5 (I think) , bin 39 and bin46, connected the phone to the usb and IT WORKED.

So, Quickpwn 2.2.5, firmaware 2.1.5 or any firmware, the bin36 and bin49 files, connecto to the Usb, select unlock and activate and whatever you want.

I would guess that the Quickpwn does the following (could be totally wrong):

Does not use Itunes,
Puts the iphone in DFU mode which I had serioues doubts I was setting it to DFU but it looked like Restore (cable + Itunes logo image) NO MATTER HOW MANY TIMES I TRIED THE DFU SETTING PROCEDURE.

Hope it helps.