Do I have to enter operatingsystem in order to access BIOS settings on a raspberry pi? I am thinking about installing ubuntu on a raspberrypi and I see that linux has equvalent to windows 10 safemode. You can boot into recovery mode by pressing "esc" over and over at startup, see link, https://www.maketecheasier.com/boot-recovery-mode-ubuntu/ . On this post they say you have to access your account and then access the bios settings, see link, What BIOS does Raspberry Pi use? .
I want to create a raspberrypi doorlock and was thinking about adding 2fa authentication for logging in to ubuntu, but im worried somone can hack the maching with access to the usbport cable. Maybe boot from their own device or insert badUsb. The machine itself is behind the locked door. Only usbport cable, 1, and a keypad, not usb, attached to pins, will be accessable. I was thinking about nfc, rfid reader, but it looks like it is possible to clone the card with physical access.
It says here that you are able to add 2fa login to ubuntu with the yubikey, see link, https://www.youtube.com/watch?v=pfVhAtJt5_o&t=137s. But I guess this doesnt help if you are able to access recovery mode and change the bios from there and swap the bootorder or something. then they can open the lock because they can make their own program for the lock in their own bootdrive.
I have also looked into USBguard, https://usbguard.github.io/. If I am able to make the usbport only accept my hardwarekey and the integrated serialnumber is recognised and block everything else.