Why is "GRUB location" unavailable in Boot Repair UEFI mode?

Question

I've been trying to dual-boot Windows 10 with Ubuntu and facing a lot of challenges with the fact that Windows 10 automatically boots in UEFI mode, and not wanting to reinstall Windows to support Legacy Boot.

My Ubuntu installation was done in Legacy mode, so I've been following instructions in this link to convert the installation into UEFI mode. So far, I've been running into two problems:

1) When running Boot-Repair in Legacy mode, the GRUB Location menu is available, but unable to apply the fixes without booting in UEFI mode. 2) When running Boot-Repair in UEFI mode, the GRUB Location menu is wholly unavailable. The title "GRUB Location" is grayed out and no information is available inside of the tab.

I generated Boot Info with the Boot-Repair program, located here.

Answer 1

The comments to your question may be helpful. Also, although it's been a while since I've used Boot Repair, it may simply not need the information on the "GRUB location" tab when run in EFI mode, so you could try it without entering that data. If you prefer to try something else, here's another way to do it:

1. Disable Secure Boot. (See this page of mine for pointers on how to do this.)
2. Download the USB flash drive or CD-R version of my rEFInd boot manager.
3. Prepare a boot medium using the rEFInd image.
4. Boot using the rEFInd medium. It should present options to boot both Windows and Ubuntu.
5. Try both the Windows and Ubuntu boot options. If both work....
6. Boot into Ubuntu.
7. Mount your ESP (/dev/sda2) at /boot/efi (you may need to create this directory). You can do this temporarily with the mount command, but in the long run you may want to create an /etc/fstab entry for this, too.
8. Install an EFI boot loader. Two options are likely to be relatively easy:
   • You can install the rEFInd Debian package or PPA to use rEFInd rather than GRUB as your default boot manager.
   • You can manually install GRUB by installing the grub-efi-amd64-signed package. You may also need to type sudo grub-install followed by sudo update-grub to fully install and configure it.
9. Test that you can boot.
10. You may optionally re-enable Secure Boot; however, if you installed rEFInd, you'll probably have to jump through some extra hoops, as described in the rEFInd Secure Boot documentation.