Grub-install documentation or override?

[mgreger]

I absolutely cannot get grub-install to do what I need it to do: Install to the 
MBR on a disk image that is loop mounted with kpartx, while chrooted into an 
ext4 filesystem on the first partition of that image. The image will be used on 
a BIOS machine but the physical host is EFI.

This is for a linux from scratch 7.7 build and so uses the grub version found 
here: http://alpha.gnu.org/gnu/grub/grub-2.02~beta2.tar.xz

I discovered the "target" argument to override the architecture by searching 
the web (it doesn't seem to be mentioned in any detail in the Grub manual), but 
I can't get it to install regardless. I get some nonsensical message about 
being unable to find 'lvm/loop0p1' although I am not using lvm in the image. 
The image only has a single MBR partition.

This seems like it should be a simple thing to do and if it is I apologize, but 
I really hate it when software tries to be clever in an effort to 'help' and 
makes assumptions that turn a simple matter into a nightmare.