-h, --help print this message and exit
-v, --version print the version information and exit
--root-directory=DIR install GRUB images under the directory DIR instead of the root directory
--grub-shell=FILE use FILE as the grub shell
--no-floppy do not probe any floppy drive
--force-lba force GRUB to use LBA mode even for a buggy BIOS
--recheck probe a device map even if it already exists
INSTALL_DEVICE can be a GRUB device name or a system device filename.
grub-install copies GRUB images into the DIR/boot directory specfied by --root-directory, and uses the grub shell to install grub into the boot sector.
should give you access to the complete manual.