I found the below chart showing the max size that each OS supports so it depends on your OS version.
BlackBerry Device Software version Media card size limit
BlackBerry Device Software 4.2.0 Up to 2 GB
BlackBerry Device Software 4.2.1 Up to 4 GB
BlackBerry Device Software 4.2.2 Up to 4 GB
BlackBerry Device Software 4.3.0 Up to 8 GB
BlackBerry Device Software 4.5.0 Up to 8 GB
BlackBerry Device Software 4.5.0.81 and later Up to 16 GB
BlackBerry Device Software 4.6.0 and later Up to 32 GB
