this is such an old device, scp/sftp, won't work. curl or basic ftp, I think are the only real solutions to get the firmware to the camera. perhaps someone may suggest the proper line to use curl?
i got the curl line I tried from here by @honken, and adjusted, accordingly, as I posted earlier:
https://forum.openwrt.org/t/support-for-the-d-link-dcs-930l-webcam/89212?u=tmomas
@psherman, i did confirm that I'm using the "A" version, not the "B" version of 18.06.