Please have a look at the firmware.
The "save" command saves the internally measured calibration data to the internal save location [0-4], recall is the reciprocal command to load calibration data from the internal save location.
The "save" command does NOT upload calibration data from outside the nanoVNA into the nanoVNA
The "data" command downloads data from thenanoVNA to the PC, there is no reciprocal command to upload data from the PC to the nanoVNA
