I have been trying to boot to debian's network installer on a thumb drive, but it always gives the message "Reboot and Select proper Boot Device". I have tried switching between UEFI and legacy boot, turning on/off CSM, turning on/off TPM, yet I always get that message. I finally tried factory resetting the settings and turning off secure boot, and now a different thumb drive with ubuntu on it that worked before now doesn't work either. I think I remember having this issue 1 or 2 years ago, but was able to fix it. Am I missing a setting?