I have pre-installed windows 8.1 on my machine and its a uefi enabled machine. I installed linux mint 17.1 on this by the side of windows 8.1.
As I was unaware about the approach to install linux mint in a dual boot on uefi system, I installed it in a way I used to install linux mint in non uefi system.
After this I was unable to boot my windows but only linux mint. After reading many post on this site I got to know that
boot-repair can fix the problem. I boot-repaired the system, by doing this I was able to see windows in boot menu but when I tried to boot it the screen gone black after colorful cross lines.
[ -d /sys/firmware/efi ] && echo "Installed in UEFI mode" || echo "Installed in Legacy mode"
The execution of the above command gives
Installed in Legacy mode.
boot-repair Advanced Options shows something like this:
How do I convert linux mint to uefi from legacy mode and be able boot windows 8.1 again with linux mint 17.1