Some weeks ago I installed Ubuntu 16.04 on my Toshiba P50t-A Notebook on a SSD (planned as Dualboot, so created all necessary partitions with gparted and some adjustments with cgdisk in cases where gparted is not suffice).
Therefore I disabled Secureboot, leave EFI-Boot in place and adapted the boot order so SSD will be booted after the USB Stick, other options (like PXE) later in the boot order.
Sometimes (like after a reset) I see the following error messages during boot:
Failed to open \EFI\BOOT\grubx64.efi - Not Found Failed to load image \EFI\BOOT\grubx64.efi - Not Found Failed to open \EFI\BOOT\MokManager.efi - Not Found Failed to load image \EFI\BOOT\MokManager.efi - Not Found
After that I need to cancel three times the PXE boot. Only after that finally the Grub Screen is shown (without image, just black background, though one of the Ubuntu boot images was installed).
The above message is not shown when I reset or switch off before the grub menu is displayed.
Originally I had to use Boot-Repair to get Ubuntu to boot at all. The EFI\Boot folder does contain the grubx64.efi file but not the MokManager.
Boot-Repair diagnostic output can be found here: http://paste2.org/ttpkpCF5
Is there any way to make the Toshiba boot in a normal grub-intended way ? I want to dual-boot using grub and avoid tricks that manipulate the windows boot file from within windows (I tried that in the past and it did not work reliably).