bcdboot c: \windows /s z: /f all

bcdedit.exe /enum firmware

bcdedit.exe /delete


bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi

bcdedit /deletevalue {bootmgr} path \EFI\ubuntu\grubx64.efi

bcdedit /set {bootmgr} path \EFI\Microsoft\Boot\bootmgfw.efi