this what they said:
"
Dear Shaher,
Greetings from iTunes Store Customer Support. My name is Divya and I am glad to assist you.
I understand that when you download "Thunderbolt Firmware Update v1.1" your mac restart. Addressing your concern is really important for me. I am happy to help you.
Shaher, as an Advisor for the iTunes Store, I help customers with questions about purchasing and downloading content from the iTunes Store, managing their accounts, and troubleshooting connection issues. Although your question falls outside of my area of specialty, I'm happy to help.
You can find troubleshooting tips, how-to articles, and moderated discussion forums on our support website:
www.apple.com/support
These resources are free of charge and available 24 hours a day, 7 days a week."