create vdisk file=<path_to_vhd>\debian.vhd type=fixed maximum=1500

apt-get install ntfs-3g parted

#!/bin/sh
cp -p /sbin/partprobe "$DESTDIR/bin/partprobe"
cp -p /lib/x86_64-linux-gnu/libparted.so.2 "$DESTDIR/lib/x86_64-linux-gnu/libparted.so.2"
cp -p /lib/x86_64-linux-gnu/libreadline.so.7 "$DESTDIR/lib/x86_64-linux-gnu/libreadline.so.7"
cp -p /lib/x86_64-linux-gnu/libtinfo.so.6 "$DESTDIR/lib/x86_64-linux-gnu/libtinfo.so.6"

#!/bin/sh
PREREQ=""
prereqs()
{
    echo "$PREREQ"
}
case $1 in
get pre-requisites
prereqs)
    prereqs
    exit 0
    ;;
esac
cmdline=$(cat /proc/cmdline)
#cmdline="root=/dev/loop0p1 loop_file_path=/debtst.vhd loop_dev_path=/dev/sda2"
for x in $cmdline; do
    value=${x#=}
    case ${x} in
        root=) value_loop_check=${value#loop}
            if [ x$value_loop_check != x$value ]
                then loop_dev=${value%p}
                loop_part_num=${value##p}
                else echo "Root device is not a loop device. loopboot hook will be terminated."; return
            fi ;;
        loop_file_path=) loop_file_path=$value ;;
        loop_dev_path=*) loop_dev_path=$value ;;
    esac
done
if [ -z $loop_file_path ] || [ -z $loop_dev_path ]
    then echo "Either loop_file_path or loop_dev_path parameter does not specified. loopboot hook will be terminated."; return
fi
#modprobe fuse
modprobe loop max_part=64 max_loop=8
loop_dev_type=$(blkid -s TYPE -o value $loop_dev_path)
if [ ! -d /host ]; then
    mkdir /host
fi
if [ "$loop_dev_type" != "ntfs" ]
    then mount -t $loop_dev_type $loop_dev_path /host; echo "mount -t $loop_dev_type $loop_dev_path /host"; echo "mounted using mount";
    else ntfs-3g $loop_dev_path /host; echo "mounted using ntfs-3g";
fi
losetup $loop_dev /host$loop_file_path
partprobe $loop_dev

update-initramfs -c -k all

title debian
find --set-root --ignore-floppies --ignore-cd /debian.vhd
map /debian.vhd (hd3)
map --hook
root (hd3,0)
kernel /boot/vmlinuz-4.19.0-14-amd64 root=/dev/loop0p1 rw loop_file_path=/debian.vhd loop_dev_path=/dev/sda2
initrd /boot/initrd.img-4.19.0-14-amd64

list volume
  Volume 1         System Rese  NTFS   Partition    549 MB  Healthy    System
  Volume 2     C                NTFS   Partition     49 GB  Healthy    Boot
select volume 1
assign mount=C:\mnt

remove mount=C:\mnt

bcdedit.exe -create -d grub4dos -application bootsector
*The entry {GUID} was successfully created.

bcdedit.exe -set {GUID} device boot
bcdedit.exe -set {GUID} path \grldr.mbr
bcdedit.exe -displayorder {GUID} -addlast

bcdedit.exe /set {default} bootmenupolicy legacy