Always append status=progress and conv=fdatasync Makes sure that the buffer is flushed to disk before finishing.

Of course. That's the right way to do it. I was pointing out that what was written isn't right in any situation and the smallest change to make it make sense would be adding <cat> in the middle

Turns out my answer was wrong too :D. Should have been <image.img cat >/dev/sda. Oh well