Can I dual boot Windows 8 and 10 from the same product key?

Question

I'm building a new PC and I don't know if I want to use Windows 10, so I got a Windows 8 disk. I also don't want to miss out on the free upgrade if I do eventually decide to use Windows 10 later.

If I:

1. install Windows 8 on one partition of my SSD
2. make an image of it
3. upgrade the one partition to Windows 10
4. copy the Windows 8 image to another partition on the SSD

will I still have the option to alternate between the two operating systems?

I've heard that after 31 days the old license expires, but according to Microsoft, after the 31 days it can still be factory reset, so I'm still slightly unsure whether my license key will stay valid and usable through the upgrade and dual boot. Does anyone know what will happen?

Also, I'll be installing some version of Linux and using Grub as the bootloader. I've multi-booted with Linux and two versions of Windows before with installing both normally rather than using an image, which made me go through both Grub and the Windows bootloader, so hopefully using images that are completely independent of each other will avoid that issue and the only bootloader I will have is Grub.

Will this all work as I'm hoping or is there anything else I can do to make it work like this?

Answer 1

Yes this will work. Though this part

copy the Windows 8 image to another partition on the SSD

will require updating the boot manager.

Alternatively, you could simply install the same windows 8 to the second partition and only upgrade that.