ok, i had problems with the other post method, but this is how i fixed my 3g and 1g iphone. with error 2001, 1600, 21. The solution using a HUB or disconecting the phone after the itunes error doesnt worked for me

The MUST get:

1. A mac with leopard WITHOUT OS 10.5.6 (format, get another one, i dont know )
2. itunes 8.02
3. The Firmware 2.2.1 for 3g or 1g iphone (iClarified - iPhone - Where To Download iPhone Firmware Files From)

NOTE:

if you already got the 2001 error, you must do this all again from 0. this happens when you try to jailbreak or unlock iphone with a 10.5.6 mac.

HOW TO:

1. Put in a folder the firmware you downloaded and QuickPwn or Pwnage (i prefer QuickPwn)
2.. GET the mac with 10.5.5 or later OS and restore from 0 your iphone.
3. Once Finished, just open QuickPwn and let him do the stuff
4. Play with your new jailbroken iphone

NOTE: For the ones doesnt know how to use PWNage here is a nice guide:
2G: iClarified - iPhone - How to Unlock/Jailbreak Your 2.x.x 2G iPhone (Mac) [Updated 2.2.1]
3G: iClarified - iPhone - How to Jailbreak Your 2.x.x 3G iPhone (Mac) [Updated 2.2.1]


Thats all, the trick is only start from 0 all.

bye