Counteracting hard disk malware lodged in the firmware with firmware write-protection switch [on hold]

1. Found none myself but are there any hard disks with a firmware write-protection switch?¹


2. Would I be right in expecting such physical switch to make my hard disk immune to malware that infects the firmware, such as the one used by the so-called Equation group?


3. Can the file system of a hard disk be modified, for instance from NTFS to ext4, and formated if the firmware area is read-only?

¹ The idea behind a firmware write-protection switch is to prevent the firmware of the HD from being updated when the switch is set to lock. I don't know if it exists or not, I could not find information regarding this issue hence the question on whether hard disks with such lock mechanism exist.