Lost EFI entry in boot menu after removing and re-connecting drive

Problem: Qubes OS entry disappeared from the boot menu.

I had installed Qubes concurrent with a Windows 10 installation and another Linux and the boot menu listed all 3. Everything worked fine. But one day I took out the drive, put in another and booted from that, and then put the original drive back in. From then on, the boot menu only had Windows and the other Linux, but Qubes OS had mysteriously disappeared. No software was installed during this time.

I was able to follow the ‘Installation finished but “Qubes” boot option is missing and xen.cfg is empty’ troubleshooting instructions to recreate a Qubes entry.

But I’m puzzled as to what could make the entry disappear in the first place and what can be done to prevent it?

I am facing the same issue since past weeks, I have not able to figure out the what is causing the problem but I did find the solution.

Boot into the installation media, Go to shell

efibootmgr -v

if the qubesOS entry is missing add it manually

efibootmgr -v -c -u -L QubesOS -l /EFI/qubes/grubx64.efi -d /dev/sdd2 -p 1 #grubx64.efi for  qubes R4.1, xen.efi for Qubes R4.0 Sdd is the drive and p 1 is the partition no

Reboot, You will find the boot entry for qubes.

source

Edit : I think the it’s the motherboard firmware causing this particular issue, Please update your motherboard bios firmware to latest and disable C state option.

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Yeah, the efibootmgr command usage is described in “UEFI troubleshooting” and it does add the boot entry.

You may be on the right path as to the cause. My HP BIOS doesn’t label them as C-states.

I also wonder if BIOS “Dynamic Runtime Scanning of Boot Block” could cause this.