So, here's my question... Have an already jailbroken (using pwnage tool) 3g running fw 3.0.1. No need to unlock as ATT is my carrier. Want to update to 3.1.2 but with the least amount of hassle since it's highly modded and I'm lazy...

I'm on OSX and downloaded PwnageTool 3.1.4 as well as the 3.1.2 ipsw. Ran Pwnage on the ipsw to generate my custom restore file.

Can I just go into iTunes, option-click Update, point to the custom ipsw and go? What is the difference between doing that and putting the phone into recovery and using Restore to install the new ipsw? If someone could shed some light that would be sweet. Thanks much.