The story is fake, there is no such a thing as universal bios, every bios is different, so you can't make virus that would rewrite bios on every computer because every computer(or let's say motherboard) is different. The attack would be possible if it would be written for specific single mobo and it wouldn't be able to transfer from computer to computer. The voiceband transmission between computers is possible but it would not be effective in terms of remote control. You just can't send a file via speakers and microphone, technically you can, but the computer on the other side would have to be running program that would be able to create file based on received audio signal and there are not yet enough sophisticated programs that can do this.