> As per the article, to actually prevent ring -3 malware. The implemented signature is the best way to do this. If we could run our own "libre" code there, so could the attacker.
That's completely false; allowing the execution of libre software doesn't worsen security, and the security-by-obscurity model doesn't improve it.
> allowing the execution of libre software doesn't worsen security
It does if I get temporary physical access to your machine and flash something that can spy on you, or if the method of flashing it can be done via your OS and I hack that. Those are two HUGE flaws.
That's completely false; allowing the execution of libre software doesn't worsen security, and the security-by-obscurity model doesn't improve it.