Oddly enough I tried all the fixes when I got this efi error out of the blue. I have a dual boot, using win 7 as my primary and win 10 on another drive.
I downloaded a boot manager after seeing that somehow the drive letter had gotten changed when I decided to check the boot status. I did not have this issue until the latest update.
Changed it back and all was well.
Did this solve your problem?
Sorry this didn't help.
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