How to remove options for choosing operating systems before booting?

Question

ubuntu

After removing the hard disk with Windows from the computer (only the disk with ubuntu remained in it), before loading, it displays a menu with a choice of Windows or ubuntu, although it was not there before. Before extracting, I simply set the order of loading disks in the BIOS. How to remove this menu with a non-existent Windows?

Answer 1

Delete menu item in bios. Look for something related to UEFI.
I will add: the efi windows bootloader can be on a hidden efi partition on the Ubuntu disk.
I'll add: sudo update-grub