I am not saying that this is the solution. I have standard BIOS on my machine. I cannot say that I have tested this on UEFI but I thought that the command was
Change sda to sdb, etc., if you do not want grub installed into the first hard disk (sda). when I leave off the /dev/sda bit I get the "Install device isn't specified" error.
sudo grub-install /dev/sda
for anyone following this thread, there is also these links