Once you select Modem in USB section, it stays selected. There is no need for OK Button. Revert to PDA is required to be done, otherwise the phone will not be recognized in Mass Storage Mode when connected to a PC for file transfers. For reverting back to PDA mode, again dial **87284 and just select PDA and then back capacitive button on the phone. Do this once you are through with CDMA Workshop and the phone has re booted.