Yeah, that's wishful thinking. Because even if there were such a switch, it would be deliberately perverted. E.g. some SD cards have a "write-protect notch" th

Yeah, that's wishful thinking. Because even if there were such a switch, it would be deliberately perverted. E.g. some SD cards have a "write-protect notch" the status of which can be changed by physically moving a sliding tab. Very reminiscent of write protect on floppy disks. Here's the gotcha[1]: The presence of a notch, and the presence and position of a tab, have no effect on the SD card's operation. A host device that supports write protection should refuse to write to an SD card that is designated read-only in this way. Some host devices do not support write protection, which is an optional feature of the SD specification. Drivers and devices that do obey a read-only indication may give the user a way to override it. [1] https://en.wikipedia.org/wiki/Secure_Digital#Features https://en.wikipedia.org/wiki/Secure_Digital#Features