I have run Boot Repair on my machine and then rebooted my machine with my Live USB out.
From this point, I was first presented with a screen that said
1) "Shim UEFI Key Management" then was presented with
2) Boot Manager screen with two options: a) Unknown Device and b) Windows Boot Manager. Selected "Unknown Device" as option (b) did nothing.
3) After this, saw a GRUB ver 2.02 screen with the first option of *Ubuntu, which then eventually got me into Ubuntu.
The above sequence of steps occurs everytime I reboot my machine.
Why all these steps?
FYI, here is my boot-repair info: http://paste.ubuntu.com/10562192/
You will notice that on lines: 549, 741 and 776, I am getting the line:
Boot0000* Unknown Device: HD(1,800,100000,aa8f4a18-e5fc-41ff-bb2d-826eab7312c9)File(EFIubuntushimx64.efi)RC
Would this be the reason I am getting the "Unknown Device" in my Boot Manager?