Your Boot Repair output looks correct, at least at first glance. Chances are the firmware on your computer is defective. I recommend you try going to the manufacturer's site and updating the firmware. (The manufacturer probably calls the firmware a "BIOS," although technically it isn't a BIOS.) If that fails, I recommend you return the motherboard and buy a new one from a different manufacturer, since you shouldn't be accepting defective merchandise. (Note that the defect is something that would be in all motherboards of that model with the same firmware version; I'm not talking about a sample-specific manufacturing defect.) If you return the computer, be sure to tell the manufacturer why you did so. They'll keep delivering junk if people keep accepting it; and if you don't tell them why you returned junk, they won't know what needs fixing.
If you really MUST keep that motherboard, you can work around the problem as follows:
- Boot an Ubuntu emergency disk.
- Mount
/dev/sda1
somewhere convenient -- say, /mnt
.
- Type
sudo cp -r /mnt/EFI/ubuntu /mnt/EFI/BOOT
.
- Type
sudo mv /mnt/efi/BOOT/shimx64.efi /mnt/efi/BOOT/bootx64.efi
.
This procedure copies the boot loader to the fallback filename, which the firmware should launch when it fails to launch it under the name registered in NVRAM. This workaround, however, means that GRUB updates (that is, updates to GRUB, not updates to GRUB's configuration) won't be fully installed unless you repeat these steps.