boot - Ubuntu 18.04 not booting after Windows 10 install

After installing Windows 10 on a new hard drive, Ubuntu 18.04 will no longer boot.

The computer boots to Grub 2.02, but to a version I'm not familiar with, showing the EFI images.

Choosing the different options results in the following:

• "EFI/ubuntu/fwupx64.efi" returns me to the menu, with no message


• "EFI/ubuntu/mmx64.efi" shows Shim UEFI key management screen


• All "efi/Efi//.efi" options result in a file not found error


• The Windows options boot to Windows correctly

I've tried Boot-Repair a couple of times with no luck. The last report from Boot-Repair can be found here.

Is there any way to completely reinstall the EFI setup?

Update:
Running grub-mkconfig produces the same incorrect menu entries. The config is generated using the files in /etc/grub.d. My directory only contained /etc/grub.d/25_custom, which is the only file in that directory. It looks like my /etc/grub.d templates are hosed, and I need to find a way to regenerate them. Is there a command to rebuild these templates?

As pointed out by @karels comment, the grub config is generated using the files in /etc/grub.d. My directory only contained /etc/grub.d/25_custom, which contained the strange menu entries shown in the screenshot. It looks like my /etc/grub.d templates were maybe hosed by boot-repair.

I fixed this by:

1. Boot with Live CD (probably important to use same Ubuntu version)


2. sudo mount /dev/sdxx /mnt


3. sudo cp /etc/grub.d/* /mnt/etc/grub.d/


4. sudo update-grub


5. Reboot & relax after 48 hours of pain