Obscure error: dd: failed to open: No medium found
I got this error message when I wanted to use
dd to copy a raw image to a MicroSD card. You will see this message if you have unmounted the card with a file manager like Nautilus.
Unmount the card via the terminal:
dd command will work now.
Another variant of this error can be seen when using
bmaptool: ERROR: cannot open destination file '/dev/sdd': \[Errno 123\] No medium found: '/dev/sdd'