Question Boot option listed in BIOS even though no drives are connected


Jul 17, 2013
Hi folks, I think I'm in over my head here and would love to understand what is happening. I'll give the short version first, but the backstory might be required here. Please forgive me if I'm posting in the wrong place.

Short version:

I have disconnected all of the disks/drives/devices from my system, but in my BIOS boot priority menu there is still a listing for "ubuntu". How is that even possible?

Long version:

A while back I was playing around with having a dual-boot to Ubuntu setup on my existing Windows-only machine. I opted to install this on a second hard drive, as the Windows disk was an already-full SSD. I remember having a lot of trouble getting the GRUB menu to load properly and see both OS's, and I remember having to convert my Windows disk from MBR to GPT (not even sure why it was MBR to begin with?). Eventually I got it working, but I admit I was probably following guides without fully understanding what I was doing.

A little while later, the disk with Ubuntu failed. I'd stopped using it by then, so I simply disabled it in the boot list in my BIOS and things continued to work fine loading right to Windows. Until the other day, when it stopped booting altogether. I went through various steps trying to get my old Windows install to boot, and eventually just decided to reformat and go with a fresh install.

In making sure things are all fresh and won't run into a similar problem with my new install, I unhooked all my drives except the SSD Windows will be on, deleted all partitions and formatted the disk... but when I load my BIOS, it still has an "ubuntu" boot option. Then I unhooked even disk, so nothing at all is connected, and the 'ubuntu' boot option is still there... how is that even possible?

I'm afraid I cannot recall exactly what I did back when I was setting the dual boot up, but could I have somehow baked a boot option into my BIOS? Can I even undo this safely?

My motherboard is a GIGABYTE GA-X79-UP4, purchased in 2013.

Any help would be greatly appreciated!