Before pogiako piped up, I tried this approach (unsuccessfully it would
appear):
> http://debian-handbook.info/browse/stable/sect.config-bootloader.html
>
> sudo grub-install /dev/sdb
> [password]
> Installing for i386-pc platform.
> grub-install: warning: this GPT partition label contains no BIOS Boot
Partition; embedding won't be possible.
> grub-install: error: embedding is not possible, but this is required for
cross-disk install.
I have grub2 installed on the main Trisquel 7 OS on which I am attempting
this.