If I restore my iPhone 3G, which OS software will it have on it?

[hellothere:t]

My Mac will not accept the iTunes 10 download, and therefore I couldn't update my iPhone to OS 4.2. So, I updated my iPhone 3G to OS 4.2 a few weeks ago on a Windows 7 laptop with iTunes 10. Now, my iTunes will not recognise my iPhone. So, I want to restore my phone on the laptop so I will be able to use it on my Mac. So, if I restore my iPhone 3G, which OS software will it have on it?

 

[Emily1]

Restoring your iPhone will not downgrade its firmware, so it will have the same operating system on it as it did before you restored it: iOS 4.2.

 

[tanner]

th latest version you had set on it so 4.2