Exit DiskPart tool by entering exit
and at the command prompt run the following:
cd /d b:\EFI\Microsoft\Boot\
bootrec /fixboot
Delete or rename the BCD file:
ren BCD BCD.bak
Use bcdboot.exe
to recreate BCD store:
bcdboot c:\Windows /l en-gb /s b: /f ALL
The /f ALL
parameter updates the BIOS settings including UEFI firmware/NVRAM, /l en-gb
is to localise for UK/GB locale. The localisation defaults to US English, or use en-US.
Reboot and cross your fingers.
This gave me headaches. I was going in circles for a long while and there. isn't a lot of reliable info about fixing UEFI/Windows 8 at the time of writing.
[EDIT]
To re-enable Hyper-V, I also had to run the following:
bcdedit /set {default} hypervisorlaunchtype Auto
bcdedit /set {default} nx OptIn