Cant make use of grub-mkimage

I am trying to create portable grub mbr with grub-mkimage to chainload as bootsector from windows. But when booting I get stuck at a black screen with bold "GRUB" and blinking curser. No key responce.

My codes:

grub-mkimage -p=(hd0,msdos9)/boot --target=i386-pc -o core.img biosdisk minicmd part_msdos terminal ntfs ext2
copy boot.img test.mbr
dd if=core.img of=test.mbr bs=512 seek=1

I made this work once, but cant remember how. How can i make a grub mbr without linux.
I used busybox for dd.