Boot in windows
open command prompt as administrator
bcdedit /set {bootmgr} displaybootmenu yes
press enter
output should be command completed successfully
now go to advanced settings
in the section startup and recovery
click settings
make sure the time to display list of operating systems is set to 30 seconds
go to control panel ,go to power options
disable fast startup
restart your computer
but in my case the problem is not solved
still showing just one option windows 11 in boot menu
when i have duel boot installed fedora 40 workstation
so booted to windows again
open command prompt as adminsitrator
bcdedit /enum firmware
in case of fedora
you will see
\EFI\fedora\shim.efi
now type
bcdedit /set {bootmgr} path \EFI\Fedora\shim.efi
if this command is successful you will see duel boot menu again
if you want to go back to windows only boot menu
bcdedit /set {bootmgr} path \EFI\Microsoft\Boot\bootmgfw.efi
then you will see windows only boot menu
however to solve this properly
you need to install grub from your linux partition
