optional EFI Boot Services EFI Runtime Services Winload.efi Bootmgr.efi WinPE? Bootmgfw.efi Loader.efi EFI DXE Dispatcher EfiGuardDxe.efi Ntoskrnl.exe PG DSE HAL.dll EfiDSEFix.exe UM-KM boundary Kernel mode User mode load hook patch syscall No Yes patch