A natural question is whether Secure Boot is the right place to protect against the type of attack mentioned in the post. Given that we've already invested a lot of effort in fixing kernel privilege escalations, and any program able to install BIOS rootkits can access all data and modify any program anyway, what justifies the extra complexity of Secure Boot (which includes all the extra design necessary to make it secure, such as OS'es robust to tampering even with kernel privileges)? I mean, why invest so much in Secure Boot when you could harden your kernel to prevent tampering BIOS in the first place?