im running osx and im wanting to put the new 2.2 firmware on my 1.1.4 unlocked jailbroken iphone

i dont mind losing all the data on my phone and i dont mind not having it jailbroken anymore - i just need it on 2.2 and unlocked so i can use different sim cards

what is the best way of doing this? is it safe? do i need to upgrade to 2.0 then 2.2?

thanks