Visit myDashboard to update your GDL 39 Software.
GDL 39 software updates are performed through the Garmin aviation portable or mobile device(s) compatible with your GDL 39 receiver. You will need to connect your compatible device when updating your software at myDashboard.
For a list of compatible devices (excluding GPSMAP 396, 495 and 496) click on the Compatible Devices tab on the GDL 39 product page . Garmin Pilot has a separate menu to download and update the GDL 39. All other devices download the GDL 39’s update when the display itself is updated.
The GDL 39 will not update without external power connected.