I have an HP Zbook with Windows 10 preinstalled. I have succesfully installed Ubuntu 16.04 in it, but when booting the computer, no GRUB menu shows up and it boots directly to Windows.
I have disabled the Fast Startup option and tried everyhting I was able to make it work, but with no success. I am able to boot Ubuntu by entering the boot menu at startup. I copy here the results of efibootmgr and update-grub for info.
Does anyone know how can I have GRUB to select an OS to boot?
You just have to modify the boot device order in the UEFI Settings. You should be able to access the UEFI Settings from the "boot menu", or restart from Windows while holding Shift, then navigate through the menus to get to the UEFI Settings. From there you should be able to find the boot device list and change their order so "ubuntu" is on top of the list.
I have 3 answers(solutions):
1) Try to "brute force" it with boot-repair. Go in ubuntu and run commands, and choose recommend repair. And hope it helps.
2) If it does not work, you could manually replace EFI/Microsoft/Boot/bootmgfw.efi file with grubx64.efi file (take a little tour into esp partition and look for .efi files in grub folder or something. If grubx64.efi doesn't work, try other .efi files). WARNING: backup bootmgfw.efi first, because without it you cannot boot in windows (without windows recovery usb).
Why will this work? UEFI firmware is (in your case) set to boot bootmgfw.efi file, so if you replace if with grub.efi, it will boot Grub (its a mind trick). Note: I didn't try this with Grub, but I did with rEFind. It is also possible that Grub doesn't work, so it currently over jumps grub into Windows.
3.) Try rEFind:
sudo apt-add-repository ppa:rodsmith/refind
sudo apt-get update
sudo apt-get install refind
This may solve the problem. If not see manual install of rEFind section at link:
www.rodsbooks.com/refind/installing.html#linux
