How to fix Error 1013 in iPhone 4

[Smokin JOE]

I have been using the iPhone 4 since last few months and recently tried to upgrade the iPhone iOS4 to iOS 4.2.1 and it is giving me an error message in between which says that "the phone iPhone could not be restored an unknown error occurred (1013)". What is the procedure to fix this error 1013 and also i would like to know whether the iOS 4.2.1 is good enough and please tell me what am i missing.

[Wiro]

The 1013 error occurs because the HOSTS file from our pc / mac is modified and Apple has put a new security in the baseband that throws the error 1013. Using the below steps you can get this problem fixed HOSTS file as source and we can try again to get the 4.2.1 without errors.
Process:

1. Tinyumbrella open and go to the Advanced tab
2. Deactivate the tab "Set Host to Cydia on ...."
3. Click on Apply Changes, and close tinyumbrella
4. Finally try to get 4.2.1 again and the problem should be fixed again

.

[Caelaan]

Yesterday and this morning I was trying to update my iphone 4 to 4.2.1 but this gave me an error 1013. My iphone is not jailbroken, but if I used to save SHSH tinyumbrella of 4.1 per case. It is for this reason that gave me the error? I did not think of tinyumbrella to do something to your hurting. I've had since my first jailbreak iphone edge (of necessity) and now with this it was clear that he preferred a clean system. I do not care about the baseband and jailbroken. i want my iPhone 4 to be upgraded to 4.2.1 any how.

[Macarenas]

I had this problem but i got it fixed by performing the steps which are mentioned below

1. Browse to the Applications folder on your Mac and then navigate to the Utilities folder.
2. Launch the 'terminal'.
3. Type the command sudo nano / etc / hosts" then press the hit button.
4. Provide the password when it prompts you for the password.
5. with the help of the down arrow key find the line "gs.apple.com.
6. Once the cursor is over, make sure the line begin with "#" before the text.
7. Save the file , you can do this by pressing CTRL + O.
8. Now Exit the nano editor.
9. Restore your iDevice.

[popau1]

Thank you Wiro, you saved my life... I spent my whole day trying to restore my phone... Be machintoshly blessed

[gmcmoz]

windows tutorial please?

[Maq.H]

windows tutorial please?

The fix of this error on Windows Computers is mentioned here:
Getting error 1013 in itunes when installing ios4.2.1

Hope this helps. For more info, you should also check out these threads:
iphone gives error 1013
error 1013 occured while installing iTunes