I have been struggling with the following issue for a while:
I have installed Ubuntu 16.04 in dual-boot with Windows 10 (x64 version) on my HP laptop equipped with a UEFI instead of a good-old BIOS, and I can't seem to access the GRUB2 menu from which I can launch either Ubuntu or Windows 10.
The boot process is always hijacked by the Windows Boot Manager.
I've tried many solutions after reading so many similar questions on different forums and in different tutorials.
1- I turned off Windows 10's fast-startup feature.
2- I changed the boot order using an elevated command line in Windows 10:
While keeping secure boot enabled :
bcedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi
While disabling secure boot from the UEFI settings :
bcedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi
3- I've tried accessing Ubuntu in LiveCD mode from a bootable USB and used the utility "boot-repair" to repair the boot-order and ended up with having an error:
an error occurred during the repair.
Please write on a paper the following URL: http://paste2.org/WXMwaeOv
In case you still experience boot problem, indicate this URL to: boot.repair@gmail.com
You can now reboot your computer. Please do not forget to make your BIOS boot on sdb (1000 GB) disk!
If your computer reboots directly into Windows, try to change the boot order in your BIOS. If your BIOS does not allow to change the boot order, change the default boot entry of the Windows bootloader. For example you can boot into Windows, then type the following command in an admin command prompt:
bcdedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi
Thank you very much ahead for your help and effort!!