Đang có con P9981 os 7.0.0.579, mình muốn up lên os 7.1 mà ko dc. Dùng BDS thì nó bảo This BlackBerry® Device Software upgrade includes new features and significant enhancements to the BlackBerry® solution and, as such, is only available to users with an active BlackBerry subscription. To learn more about BlackBerry® service, please visit www.blackberry.com/service. Mấy pro giúp mình với nhé
