I believe it can be used. Because when the phone was originally made the only available cards were up to 256 MB's and they said it can do up to 256..because thats all that was avaliable...now they are up to 1 Gig.
☹️ i just got my v635 i have service with tmobile i bought it on ebay from a company in china. i knew it can have upgradapble microsd cards installed but i dnt knw were to look and its not in plain sight. do i have to take the phone apart?