A method of upgrading firmware of an adapter includes transmitting a set of n data blocks of first upgrade file to the adapter, receiving a first response information of the adapter based on the set of n data blocks, and determining that the updating procedure of the adapter fails when the first response information indicates that the adapter fails to receive all of the n data blocks. In the method, a mobile terminal transmits the upgrade file to the adapter and the adapter sends determination information to the mobile terminal after the adapter receives the upgrade file having a predetermined size. In a time interval, if the mobile terminal fails to receive the determination information or the adapter does not receive the upgrade file, the upgrading firmware of the adapter fails.