If it confirms all the last 6 parts & Xbox live failed or failed to download an update when it reaches to this part that would be an issue with the coming part which is the NAT.
If the NAT is not open (Strict or Moderate)
- You have to contact your ISP or router manufacturer to open or forward the 3 Xbox live ports which are:
- UDP 88
- UDP 3074
- TCP 3074.
Or you can check it on www.portforward.com, then go on the Dashboard of your Xbox 360 console to “System” area then “Network Settings” then "Test Xbox Live Connection".
If you faced any other kind of troubles with this part failing even after you tried these steps please don't hesitate to leave a comment.