>even good old BIOS is susceptible to rootkits Those common rootkits were not in the BIOS firmware, they were just malicious code on the hard drive. But the c

>even good old BIOS is susceptible to rootkits Those common rootkits were not in the BIOS firmware, they were just malicious code on the hard drive. But the code was written on drive space not used by the file system so it withstood malware scanning of the volume and often reformatting/restoration too. The Master Boot Record (fist 440 bytes of sector 0) would often need to be renewed from trusted media, and the malicious code zeroed using a raw disk editor which can address sectors which are not within the file system. Or the shotgun approach could be taken and the whole HDD zeroed.