Ubuntu dual boot problem

[hemanthyarlagadda96]

I tried bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi. Even then it disappears after every restart. What to do?

 

[Rocky Bennett]

What kind of hardware is this? Have you checked your BIOS? Did you disable fast start-up? What version of Ubuntu?

 

[hemanthyarlagadda96]

What kind of hardware is this? Have you checked your BIOS? Did you disable fast start-up? What version of Ubuntu?

Yes I disabled fast start-up. Ubuntu 18.04.1 LTS.
Lenovo Z 50-70.