Problem ATV2

Sorry, i have an ATV2, i did the jailbreak in 2011 of the 4.2 or 4.3 version. Actually I want to pass to version 5.2. I downloaded the last version of  Seas0npass, I did all passages and a the end, seas0npass don’t open itunes to complete the process. How can I do?

I also tried to download the file .ipsw of 5.2 version from internet and upload with itunes on the apple tv but there is always an error (11, 21, 1600)