Sierra Wireless GSM modem EM7455 + Android Integration Error

EM7455 connect on Single Board Computer(NanoPC-T2) through USB. I have attached AndroidRIL_5.1.11 binary files in my android and kernel source after build it and run on my android device.Below error messages received on android Log: # dmesg | grep sierra [ 1.184000] usbcore: registered new interface driver sierra_net [ 40.552000] usbcore: registered new interface driver sierra [ 40.564000] sierra: v.1.7.42_android_generic_2:USB Driver for Sierra Wireless USB modems [ 47.308000] sierra_net: module is already loaded [ 87.844000] sierra 1-1.1:1.0: Sierra USB modem converter detected [ 87.872000] sierra_remove_sysfs_attrs usb_get_serial_port_data(port_tmp) = 0xd8c90000 [ 87.880000] kfree at sierra_remove_sysfs_attrs [ 87.884000] sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 [ 87.892000] sierra 1-1.1:1.0: device disconnected [ 90.920000] sierra 1-1.1:1.0: Sierra USB modem converter detected [ 90.948000] sierra_remove_sysfs_attrs usb_get_serial_port_data(port_tmp) = 0xda6b8d80 [ 90.956000] kfree at sierra_remove_sysfs_attrs [ 90.960000] sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 [ 90.968000] sierra 1-1.1:1.0: device disconnected 127|root@nanopi2:/ # dmesg | grep sierra [ 1.184000] usbcore: registered new interface driver sierra_net [ 40.552000] usbcore: registered new interface driver sierra [ 40.564000] sierra: v.1.7.42_android_generic_2:USB Driver for Sierra Wireless USB modems [ 47.308000] sierra_net: module is already loaded [ 87.844000] sierra 1-1.1:1.0: Sierra USB modem converter detected [ 87.872000] sierra_remove_sysfs_attrs usb_get_serial_port_data(port_tmp) = 0xd8c90000 [ 87.880000] kfree at sierra_remove_sysfs_attrs [ 87.884000] sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 [ 87.892000] sierra 1-1.1:1.0: device disconnected [ 90.920000] sierra 1-1.1:1.0: Sierra USB modem converter detected [ 90.948000] sierra_remove_sysfs_attrs usb_get_serial_port_data(port_tmp) = 0xda6b8d80 [ 90.956000] kfree at sierra_remove_sysfs_attrs [ 90.960000] sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 [ 90.968000] sierra 1-1.1:1.0: device disconnected Anyone known how to solve this error,help me. Thanks!