If the internal storage of your 4NSF is full, you may need to use a microSD card for map updates.
: Once recognized, the app will show all available updates. Click Install All or select specific map or software updates.
: Wait for the installation to finish. Map updates are large files and may take considerable time depending on your internet speed. 2. Using a Memory Card (For Large Updates)
Insert a compatible microSD card (up to 32 GB is typically recommended for older units) into the device's slot.
: Launch the app and click Add a Device . The software should detect the 4NSF and display its serial number.