On Thu, Mar 12, 2015 at 12:35 AM, Moritz Bartl
(**) Nobody has actually proven that you can circumvent the read-only bit and simply write with modified kernel drivers ("please don't write ... The (micro)SD exposes registers for permanent write protection (cannot be undone) and temporary write protection. If you set TMP_WRITE_PROTECT and expose the SD card as USB device (not as mmc card), the registers cannot be accessed from the host, so they cannot be changed. For an example of this, see https://github.com/Nephiel/sdlocker-tiny . Maybe there's a nice little SD card USB reader with a firmware that can be patched for this.
I wish to look at this further, but if these are normal mmc / usb / ata / scsi commmand opcodes (not actually requiring a physical burning interface), than you can do this commands over camcontrol freebsd or maybe [h|s]dparm linux without special dongle.