Do note that write-protect switches often only ask that software not write to the drive (Host protect), and are not sufficient to protect against a malicious entity.
Unless an examination revealed otherwise it is wise to assume that the write protection media is a software protection, not a hardware protection.
SD cards have a physical switch to write-protect them, but the logic & protection is done in software.
For example, there's a project that provides replacement firmware for Canon cameras - http://chdk.wikia.com/wiki/CHDK - stored on the SD card. The new firmware is selected by moving the write-protect switch on the card. In either configuration, the camera can still save new photos to the storage.
Unless an examination revealed otherwise it is wise to assume that the write protection media is a software protection, not a hardware protection.
http://security.stackexchange.com/questions/4248/how-reliabl...