Windows - W10 delete Grub settings

Scenario: You have installed W10 beside Linux (Ubuntu or Ubuntu based) but after this job, Grub disappear and you are not longer able to select the S.O. at the boot. 

• Start with W10
• Open a DOS prompt with administrator privilege
• execute this command:
• bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi
• Restart your computer with a live Ubuntu distribution
• Open a terminal (Ctrl Alt T)
• Regenerate Grub with this command:
• sudo update-grub