My objective is to install Grub 2 on an initially blank drive and then add the boot partition for UEFI so that the UEFI .img can be added and everything can boot as a standalone.
There are instructions at:
MemTest86 Grub Install with Ubuntu Linux
However, these end up with the UEFI boot option as as a sideline GRUB install from the other boot options and not as a standalone.
There is some information about how to install the UEFI .img (like Memtest86+) on top of a fresh install of Ubuntu. Rather I would like to use the root terminal to just add GRUB and configure it from Ubuntu so it is ready to work from a standalone disk with the one UEFI partition and the GRUB boot area:
Wiki Community GRUB installing
The above link is very hard for me to understand. I am looking for simpler instructions or suggestions. Thank you for your suggestions or recommended specific steps.
Update: I made sure that the GRUB version was updated to the latest:
/mnt/boot/memtest86# grub-install --version
grub-install (GRUB) 2.04-1ubuntu26.15
The grub-install proceeded to install GRUB in the boot sector with the force option, and of course specifying not the UBUNTU boot disk, but rather a different SATA disk that I would transfer to the new computer to boot. I am able to boot to the "Grub>" prompt now to manually issue the commands. However, the last command, the chain loader is not working.
On a different computer, everything works fine. But I want to return the USB stick that I purchased to get a refund instead of installing memtest86 V10 there as PassMark, the software developer, supports.
I also found a similar question at this site memtest efi grub installation; however that question dead-ended without a real answer.
Update 2:
I found some other reference(s) that might be helpful:
boot-able setup for BIOS and UEFI
SOLVED: Grub 2 gives Error: Invalid Signature
How to get a UUID from a device from the GRUB2 prompt
I still have not been able to get the chain loader to work, even with the force option, even with boot after. With the force option there is no output except another "grub>" prompt. If I remember correctly, boot just goes to a blank screen.