Reset or clone UEFI install using MBR partition from external drive?

Here's the result of pressing F12 at boot time - the "one time boot menu":



Obviously this is with secure boot off, legacy boot options on in BIOS settings. I tried both ways, turning it back to Secure Boot on - either way, when I select "Windows Boot Manager" from this list I get a message that says "Selected boot device failed - Press any key to reboot the system."

The only viable method of booting is to boot, wait for the "No bootable devices" error, and hit F1 to retry boot, after which Windows happily boots.

Honestly, I can live with that, but if we can solve the issue completely, that would be gravy. Thanks so much for your attention thus far!

In order to view a boot entry in BIOS, you first have to highlight which entry you want to view:





You should see something similar. I suspect that your entries for Windows Boot Manager are probably still pointing to your old system partition. Unfortunately, you can't edit an entry. You can only delete it and add a new one.

Aha! Thank you, I was not aware that you could click on the entry.

I get this:




What would be the correct way to add a new entry?

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I found the button to enter the filesystem on the GPT partition...should I pick BOOTMGFW.EFI or BOOTMGR.EFI or something else?

The path is \EFI\Microsoft\Boot\ in that case. Or, there is \EFI\Boot\BOOTX64.EFI.

There is also a BOOT directory that just contains EASWINPE.DAT which I assume is recovery related.

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Update: none of the options seem to work. BOOTX64.EFI, BOOTMGR.EFI, BOOTMGFW.EFI. I tried setting each one up as the only boot sequence option, and rebooting, but I get the same "strike F1 to continue" error. Didn't try continuing to boot, just went back into BIOS at that point...

There is a MEMTEST.EFI file, and if I go into the en-US directory (\EFI\Microsoft\Boot\en-US) there are some .efi.mui files. Not sure which to choose, if any...

The correct filename is given in my second screenshot. Be aware when you add a boot entry, the file system list will point to the physical disks in the system. So you would select the one that seems to correspond to your SSD. Then when you move to the next screen, there is a drop down box there that has something like FS0, FS1, etc. as choices. That box selects the partition on the disk. Then next to the box to enter the filename is a browse button. You want \EFI\Microsoft\Boot\bootmgfw.efi.

NavyLCDR said:

there is a drop down box there that has something like FS0, FS1, etc. as choices.

Thank you. I don't seem to have a choice...there is only one entry, and no way to change it.



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Oh I see it - still only one option though. FS0:

That's probably correct because it is probably only looking for FAT32 partitions to boot from and you only have 1 FAT32 partition on your system.

Heard. None of the options work though - see my edited post above. I tried all 3 EFI files and they all give the same black screen boot error.

I got no clue, then.