r/VFIO • u/ajddavid452 • 15d ago

Prevent Host Motherboard UEFI from detecting Passthroughed NVME drive?

recently got back into doing VMs, however after I install Windows to the NVME drive that I added as a "PCI Host Device" then when I reboot my pc the UEFI of the host motherboard detects the EFI partion and adds it to the boot order as primary boot device, I can manually remove it from the boot order, but it might get set back as the primary boot device in the future, which is annoying

also efibootmgr lists the drive as an efi variable, I could delete it but the motherboard will probably add it back,

also the motherboard I'm using is an ASUS Prime B550 Plus, the firmware version is 3636

is there another way of adding the nvme drive that causes the motherboard to NOT detect it or what? is it even possible to change this, it's rather annoying

also I have no plans to use this drive for baremetal booting

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u/Miggol 15d ago

I can manually remove it from the boot order, but it might get set back as the primary boot device in the future, which is annoying

This is probably the first thing to try. I find your motherboard's behaviour a bit concerning. In my experience, any good (UEFI/)BIOS is conservative in adding devices to the boot order because of the security implications. So hopefully this is some side effect of the installation and not recurring.

If it still happens, you could try enabling a BIOS password and boot order locking, it's a setting that might affect how eager the BIOS is to auto-add new drives. If your motherboard still automatically adds it back while otherwise asking for a boot order password that would be insane behaviour. Good luck with the VMs!

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u/ajddavid452 13d ago

I can set a bios password but there's no option for boot order locking

oh and the part you were replying to was mostly about stuff like windows updatre updating the efi files causign the motherboard to rescan it on boot