Repair windows 8.1 boot through Debian

I screwed up my Windows 8.1 boot with Easybcd. I checked some box that said count down from 5 seconds in the edit boot section now if I boot in UEFI boot it says windows cannot boot insert repair disk and if you don’t have the repair disk contact manufacturer. If I boot in CSM boot mode I can get to Debian 8 grub menu but windows is not on it. I want to use Grub customizer to be able to boot windows and maybe have windows show up on the Debian grub menu if it is not to risky. I cant even see window with the grub customizer program.

The easiest way to fix this would be to:-

a) extract your Windows 8 key from the UEFI firmware

b) create a Windows 8.1 USB installation media … you can download Win8.1 and create an installation DVD or USB stick on any Windows PC for free using the tool here:

(be aware - that is for PC’s that came with Win8.1 preinstalled, NOT ones that came with Win8 that has since been updated to 8.1)

c) use the USB to fix the UEFI boot files

Do you need instruction how to use Debian to extract your Windows 8.1 key from the firmware ?

And did your PC come with Win8.1 preinstalled, or Win8 that you then upgraded to Win8.1 ?

  1. I don’t know how to extract the key from the uefi boot files.

  2. I am not sure if my pc had windows 8 or 8.1 as the first version on the computer.

  3. Only linux works is it possible to do this through that?

We can extract the key via Linux, but you’ll need access to a Windows PC to create the DVD/USB stick

Reason … Microsoft don’t do an ISO image for Win8/8.1, you need to download then run a Windows only application that then downloads the Win8/8.1 image to the DVD/USB stick

So at some point you’ll need access to a Windows PC with an internet connection and a 8GB+ USB stick

If you want your Key, boot to Debian and run this command in a terminal

sudo hd /sys/firmware/acpi/tables/MSDM

your key should be contained in the left hand side in this form


If unsure which bit it is, send me the output in a personal message … do NOT post it to the public forum.

As long as you have that key, you can download/install Win8/8.1 for free