Boot from a Windows 10 Install Media (USB disk)

Select Next on language/region

Select Repair PC option on bottom left

Select Troubleshoot

Boot a command prompt

run diskpart

list disk to identify the internal hard disk

select disk # to select the proper disk

list the disk volumes – list vol

Identify the EFI hidden volume # number (Hidden, kind of 512Mb, could be formatted FAT32)

Selection this EFI hidden volume : select vol #

Assign a drive letter : assign letter=n:

exit

browse from command line to this EFI drive letter N:

Repair the BCD boot : bcdboot C:\windows /s n: /f UEFI

Repair the MBR : bootrec /fixmbr

Reboot the machine