Step 4. Type diskpart and press Enter key.
Step 5. Type list disk – Usually, it is Disk 0
Step 6. Type select disk 0 and press Enter.
Step 7. Type list volume and press Enter. Now pay attention to the volume number of the EFI partition.
Step 8. Type select volume N and press Enter. Also, type the one in your own case instead of N.
Step 9. Type assign letter=N: and press Enter. N: can be replaced by any drive letter that is not taken by any partition. Remember which drive letter you assign here for it is rather useful in the rest steps.
Step 10. Type exit and press Enter to leave diskpart.
Step 11. Now type N: (the drive lettered you just assigned) and hit Enter.
Step 12. Type format N: /FS:FAT32 and hit Enter.
Step 13. Type bcdboot C:\windows /s N: /f UEFI and hit Enter.
bcdedit /export C:\BCD_Backup
c:
cd boot
attrib bcd –s –h –r
ren c:\boot\bcd bcd.old
bootrec /RebuildBcd