Windows 10 Home (1809 version) from EFI to BIOS or to QEMU (Virtual machine)

Question

Old (Downvoted) Post:

I have installed Windows 10 in my SSD disk, and made the mistake to install in EFI mode ... (I don't want EFI in my new installation because it will be multi-boot system with some linux distributions some not available for EFI installations... I also don't see any reason to use EFI). Now I want to move this installation with the updates and my personal settings and files in another disk but not in EFI mode. The disk where I want to install windows 10 is the original disk which I purchased my Laptop and where the windows was installed. I already used the windows tool to backup the whole system but it gave just some folders and not an ISO file.

How (if possible) could I move this installation to the other disk but in BIOS and not EFI mode?

Is it easier to just reinstall (and do all the updates) from scratch (not really many programs are installed but some of them takes time like TeXlive and Qtcreator)

Finally, could it be possible and legal to move it in a KVM QEMU virtual machine (no several installations but just the one I think I have the right to have) inside an external disk (I have a disk case external or even additional -instead of DVD drive-) or again a fresh install should be used and what is the way to make this installation because earlier I had used a fake way (answered that I changed my hardware to let windows allow me to install in virtual machine).

Virtual machine is not necessary for me but preferred if possible without losing the right to use it legally.

New Post

As far as I understood from the comments, I should install from scratch because the migration from UEFI to BIOS is not officially supported and this way would be easier than editing manually (or something) my boot options. (Sorry if still not clear but don't really know how Windows and UEFI boot works).

So, my request now is to move the installation even as an UEFI installation but inside a virtual machine (UEFI boot will be iconic -not real- there). This move should be legal (I read during installation that I have the right to use my purchased version of Windows in a virtual machine as far as I use only one such installation and as far as I use it for the PC (laptop) that the installation was legal for.). Ithought I could create an ISO file from my current installation that could include my settings and programs installed and I could use it to install in my virtual box ... But seems this is not possible .... So, I am looking for the way that this installation could move in a virtual box (QEMU in debian -but I don't think it matters-) or for a way to install legally in virtual box (The way I found was to download some version of windows for vitrual machine ... but in the agreement it forbids to use your key to turn the installation into normal installation ... It has to be used only for testing purposes as they making clear in this agreement.)

PS: Also answers to turn installation from UEFI to BIOS -like the first given below- (somehow easy way) are really appreciated and accepted for the bounty too.

Answer 1

I will not try to recall the UEFI--BIOS conversion procedures because there is already an answer about it and a few useful comments. From my point of view it seems a bit complicated a procedure, but it might still be worth the effort for the benefit of learning?

Switching to a virtual environment

Converting the HDD to a virtual machine format is possibly the easiest part. Note that disk2vhd suggested in the comments converts to vhd. If you want to use the VM with qemu, it would possibly be beneficial to have an image in .qcow2 format (conversion tools like qemu-img exist, but it's a thing to watch out for).

The interesting part is after the conversion: Depending on the "storage driver" selected in QEMU it is very well possible that Windows does not recognize its (newly virtual) hard drive and thus fails to boot.

Avoiding this problem can be as easy as "uninstalling" the HDD from the running Windows before making the virtual machine image but it can get arbitrarily more complicated if that does not work.

Additionally, consider the potential necessity for resizing the virtual HDD with respect to its original one.

There is actually an advanced and nifty trick to avoid all these issues: It is using the Windows installation disk as an "image restoring" program because that is what it is actually doing behind the scenes. The difficult part is to provide an image in a suitable format, i.e. in WIM.

German computer magazine c't has published a tool for automating the process: https://www.heise.de/ct/artikel/c-t-WIMage-3863074.html (I am not sure if any resource of that kind exists in English :( ).

From a legal point of view, I understand the license just like you: Moving Windows to a VM is OK in the scenario at hand.

Dual Boot with UEFI is not as bad as it might sound

Initially, you wrote about dual-boot ideas. This is actually one of the "benefits" advertised for UEFI that you will no longer be in the situation of multiple OSes each trying to install their own boot loader in the MBR of the first disk -- with UEFI the firmware provides a dedicated menu to select the system to start from.

OT?: As a Linux-Fan, I am of course also interested to know which distribution you want to install that does not support UEFI boot as of today :) I am still on "legacy BIOS" with all of my systems, but that is mainly beacuse of reduced experience with UEFI (and no such thing like dual boot here, one "mother" OS and the rest is VMs such that all can run in parallel as long as there is enough RAM for everything).

Answer 2

Offline conversion in either direction is very easy using a Windows Setup medium and bcdboot. You also need to change the partition table (GPT/MBR) appropriately or clone your Windows partition to a new disk with the correct partition table.

Changing the partition table is the hardest part, because Microsoft does not offer tools for this. I’d use gdisk for this, but it’s an expert tool. See here.

On GPT, a UEFI System Partition is also required, formatted using FAT32. On MBR, a boot partition is created by the Windows Setup but optional. I don’t recommend creating one unless required because you can only have 4 primary partitions.

On MBR, the Windows or boot partition needs to be “active”.

Once you have the Windows partition (and optionally the boot partition) ready, just use bcdboot:

bcdboot C:\Windows

You can learn more about bcdboot here.

You can easily bring up a command prompt in Windows Setup using Shift+F10.

Answer 3

I would like to add here the option of Physical-to-Virtual (P2V).

In the comments was already raised the option of using Disk2vhd, although its output format of VHD is awkward to use in the context of this post.

You may want to check out the libguestfs project. Its virt-v2v tool might be what you're searching for:

Virt-p2v converts a physical machine to run virtualized on KVM, managed by libvirt, OpenStack, oVirt, Red Hat Virtualisation (RHV), or one of the other targets supported by virt-v2v(1).

Normally you don’t run the virt-p2v program directly. Instead you have to boot the physical machine using the bootable CD-ROM, ISO or PXE image. This bootable image contains the virt-p2v binary and runs it automatically. Booting from a CD-ROM/etc is required because the disks which are being converted must be quiescent. It is not safe to try to convert a running physical machine where other programs may be modifying the disk content at the same time.

Some random references which might be useful:

• Red Hat manual Chapter 5. Converting physical machines to virtual machines
• Tutorial: Moving a Centos physical server with Soft RAID to be a KVM virtual machine guest using virt-p2v and virt-v2v

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Another tool you may use is Clonezilla.

See for example the article Migrate to a virtual Linux environment with Clonezilla.

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As regarding licensing issues, the usage you are contemplating is in a legally gray area.

The MICROSOFT SOFTWARE LICENSE TERMS says this:

d. Multi use scenarios.

(iv) Use in a virtualized environment. This license allows you to install only one instance of the software for use on one device, whether that device is physical or virtual. If you want to use the software on more than one virtual device, you must obtain a separate license for each instance.

Strictly speaking, it may be argued that the QEMU virtual environment is not the same as your physical computer. But it may also be argued that you are only virtualizing a licensed environment and renouncing the physical one, so you are not using the same license in two environments.

As the argument may go both ways, I suggest not going too deeply into the legal issues. My experience with a previous Windows version was that after the P2V phase Windows stayed activated (but never tried it with Windows 10).