just to let you guys know, if there isn't a firmware available for your phone of the cid you want to upgrade to, then the upgrade won't be possible (that's if you want it done free anyway)
for example, if you had a w810i cid49 phone, and you wanted to upgrade it to cid52, it wouldn't be possible because there is no cid52 firmware available for w810i
however, there are some services you have to pay for out there that can get around this i think, like wotanserver or cruiserlog