The latest firmware for the flight control system including all required drivers and utilities can be found in the downloads section at Sky-Drones website: http://sky-drones.com
You need to download the latest .sap file of the firmware. Once you have it on your computer make sure to disconnect the autopilot and open SmartAP GCS again. Then go to
Firmware tab and connect the board via USB cable.
During the start-up of the board it will go to bootloader mode and the dialog will ask you to choose the firmware file to be upgraded. You will see the following dialog:
Select the firmware file to be uploaded and press Open, the update procedure will start instantly. Usually it takes up to 30 seconds, in then end you will see the status message that the firmware has been successfully updated: