Using the SD: protocol adapter. - FujiNetWIFI/fujinet-firmware GitHub Wiki
The SD protocol adapter allows the FujiNet Network device to access files stored on the SD card, if one is inserted.
DeviceSpec
When specifying a path to a file on the SD card, The following form should be used for a file in the root of the SD card.
N:SD:foo.xex
This means when accessing folders, you should extend this to:
N:SD:bar/baz/foo.xex
-Thom