I NEED Help with updating!

[Woah]

I am currently on 3.1.2 on iPhone 3GS, and I want to upgrade to iOS 5.

My 3GS is currently jailbroken, but when I try and restore it says would you like to restore & update. The thing is, if it updates whilst my phone is still jailbroken it will break it, because it's happened to my brothers.

I need to know how to restore my phone without updating it?

Thanks. x

[iYeow]

Update or restore will unjailbreak your device. Update itunes , download IOS 5 and shift + restore in itunes.