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