Fixed Disk 0: HITACHI HTS.........300
Fixed Disk 1: Samsung SSD 850 Evo 120GB

floppies_orig=0, harddrives_orig=1, floppies_curr=0, harddrives_curr=2
map (hd1) (hd0)

Error 21: Selected disk does not exist

title       Win 8.1 at SSD
map (hd0)   (hd1)
map (hd1)   (hd0)
root        (hd1,1)
chainloader +1

cp /boot/grub/grub.cfg /ssd/boot/grub/grub.cfg
    mount --bind /dev /ssd/dev
    mount --bind /proc /ssd/proc
    chroot /ssd
    grub-install /dev/sdb