Since Apple released iOS 5 firmware update a day before yesterday at WWDC 2011 many users and even developers are reporting errors 3002,1604,1600 when updating to iOS 5 in iTunes. You will be able to fix this problem using the below tutorial. However, it is not a official fix but following the steps might fix the above iTunes error codes. Follow the step-by-step guide below.






You will get the following message when iTunes error 3002, 16xx occur :

The iPhone “[name]” could not be restored. An unknown error occurred (3002/16.xx).

Fix iOS 5 Restore Error 3002,1604, 1600 In iTunes [How To] :

1) Download iOS 5 here without a developer account or UDID registered.


2) Install the latest version of iTunes here.

3) Make sure that your iPhone is disconnected from your computer and that iTunes is closed.

4) The following step is Windows specific, if you are a Mac user, you have to locate the folders yourselves :
Go to folder C:\Documents and Settings\Application Data\Apple  Computer\iTunes\iPhone Software Updates. You will see one or more files. Cut and paste them somewhere else. Do not delete them in case the steps does not work for you, you can still copy them back to the folder. You can find out your username by pressing Ctrl+Alt+Del.

5) Put your iPhone in DFU Mode (Launch iTunes > Connect your iPhone >  Press and hold the Home and Power button together for 10 seconds > Release the Power button while still holding the Home button until iTunes displays it has found an iPhone in Recovery Mode.

6) Now proceed with the iOS 5 restore.