I already had Windows 10 installed on my PC. Recently I installed Ubuntu 18.04 alongside Windows. After completing the installation the PC is unable to boot; I get this message at startup:
System BootOrder not found. Initializing defaults. Creating boot entry "Boot000B" with label "ubuntu" for file "\EFI\ubuntu\shimx64.efi" Reset System
I get the same message every time I boot.
It is important to note that I installed Windows in Legacy BIOS mode where as the Ubuntu was installed using EFI. Now, there are separate BIOS modes for each system and I am unable to boot Windows even from "Boot from File" option in the "Boot Order menu". When I boot from the legacy boot entry of Windows in boot order it says boot device not found please install operating system. I am using HP Elitebook 840 G2.
This is how the partitions on my disk are configured:
Device Type Mount point /dev/sda1 ntfs /dev/sda2 ntfs /dev/sda3 efi /dev/sda5 swap /dev/sda6 ext4 /