I know the S4 will support all the US carriers in all of their bandwidth ranges and formats (GSM, CDMA, Etc.) The question I have is if the radios for all of these bands are in the phone at the same time. If so, do we know if a rooted phone could be moved between a GSM carrier and a CDMA carrier? Real world example: If I buy the S4 on T-mobile (GSM) i know i can seamlessly move it to ATT if I want, but what if I want to go to Verizon. Is this a foolish question?