- Download Windows 11 ISO from Microsoft and write to USB.
- Boot into Windows setup utility.
- Select Repair computer –> Troubleshoot –> Advanced –> Cmd prompt.
This procedure assumes the following:
- main disk is
disk 0 - EFI partition is
part 1 - Windows OS drive letter is
c:
The following command will format the old EFI partition, mount it to s:, and copy the boot files to it.
1diskpart
2> list disk
3> sel disk 0
4> list part
5> sel part 1
6> format fs=fat32 quick label=System
7> list vol
8> exit
9mountvol S: /S
10bcdboot c:\windows /s s: /f UEFI /v
11exit