you're going to have to buy a flasher like the E3 flasher or progskeet. Before you do Google your model number + base firmware. You need to make sure that the lowest firmware that it can go to is 3.55 or below - not 3.56 or higher. It's only worth it if you can get back to at least 3.55
You will never find a legit 3.6+ jailbreak in random places on the net like youtube. You run a high risk of bricking trying to install random firmware. Please come to a site like this one for real info and downloads
Fiery the angels fell. Deep thunder rolled around their shoulders... burning with the fires of Orc.