I understand LUKs can be used to encrypt your data. But what would prevent somebody plug in a USB with and just wipe my drive?
On traditional BIOS like Lenovo, HP, Dell and even Framework you can set a supervisor password that locks the boot menu. So nobody can boot from the USB.
Coreboot is different though. I spoke with Starlabs whose computers run Coreboot, and apparently you can have the boot menu password. OTOH, Sys76’s Coreboot doesnt allow such things.
I ask because i want to libreboot my T480, but the number 1 thing i worry is unauthorized USB boot.
This one: https://libreboot.org/docs/linux/grub_hardening.html#grub-password
seems to only lock the ability to edit the grub entry freely, aka press “e” to change stuff when grub fails to boot.
Yep. Physical access is equivalent to ownership. The only reasonable thing you can do to protect against it is to prevent access. Given enough time and physical access, any system can be compromised. Encryption is the only good prevention from them reading the data, but it isn’t foolproof, and backups are the only good way to ensure you can access the data after.