[GRUB shell]

Using a Physical Hard Drive (raw-disk) with VirtualBox

To directly mount or boot a physical drive on a virtual machine (VM) run the following commands:

sudo fdisk -l

You'll see a listing of disks and partitions. Make note of the desired drive in the format of dev/sda, dev/sda1, etc.

VBoxManage internalcommands createrawvmdk -filename "</path/to/file>.vmdk" -rawdisk /dev/sda

Booting Windows raw-disk in virtualbox

insmod chain

set root=(hd0,gpt2)

chainloader /efi/Microsoft/Boot/bootmgfw.efi

boot

https://stackoverflow.com/questions/51101487/booting-raw-disk-windows-10-vm-in-virtualbox-boots-to-grub-shell