Comment by nextaccountic

here is some actual security: encrypted /boot, encrypted everything other than the boot loader (grub in this case)

sign grub with your own keys (some motherboards let you to do so). don't let random things signed by microsoft to boot (it defeats the whole point)

so you have grub in an efi partition, it passes secure boot, loads, and attempts to unlock a luks partition with the user provided passphrase. if it passed secure boot it should increase confidence that you are typing you password into the legit thing

so anyway, after unlocking luks, it locates the kernel and initrd inside it, and boots

https://wiki.archlinux.org/title/GRUB#Encrypted_/boot

the reason I don't do it is.. my laptop is buggy. often when I enable secure boot, something periodically gets corrupted (often when the laptop powers off due to low power) and when it gets up, it doesn't verify anything. slightly insane tech

however, this is still better than, at failure, letting anything run

sophisticated attackers will defeat this, but they can also add a variety of attacks at hardware level