hi, i have a 3gs, 3.0, old bootrom and i use a mac. i would like to upgrade the firmware to 3.1.2 just so i can use certain apps. i use tmobile on it, so i have already unlocked and jailbroke it. the paths i find either dont work for an old bootrom or cant be done on a mac. any advice? (please go easy on me i am pretty illiterate when it comes to this stuff)