AT&T has said today that Windows Phone 7 devices like the Samsung Focus will need special MicroSDHC cards, as removable storage is not yet supported officially by the new mobile OS.
The cards will each have "optimal performance" and current cards on the market do not qualify.
Because the Focus and other WP7 devices do not have expandable storage, you need to replace the on-board storage, which requires a full wipe of the device.
Users who try to replace the storage on their Focus are greeted by a Stop! message from AT&T, warning them that they might brick their device.












