Cannot access Windows 8.1 after installing CentOS 7.2 in dual boot

Hello everyone.

Some days ago I decided to install CentOS in my laptop with Windows 8.1. From now on CentOS will be my first choice because development reasons and other things but as you can imagine I wished to maintain Windows 8.1 for the license and other issues.

I followed the very well detailed instructions referred in the post:

I had to say that was the best instructions for the dual boot installation that I could find in internet, so I decided to perform it.

Everything worked well except for the final steps related to the yum upgrades and installation of the ntfs-3g because at that moment didn’t have an RJ45 cable and I couldn’t connect to the internet because CentOS didn’t recognized my WiFi card, so that I coudn’t access the internet.

The point is that when I boot the laptop, only the two common options of CentOS appeared in the grub boot menu. Windows was absent.

Ok, so that I could figure that something could have gone wrong and I had to fix it. No problem, I thought I could find for a workaround with internet help and some friends expert helps, (I am a newby, but a consistent one),

I added the entrance to the grub.cfg configuration file in the directory /boot/grub2, and the entrance is as follows

With this entrance the option in the boot menu appears but selecting the Windows option returns an error, (cannot see it at this moment the exact literal but I will updated as soon as I closed this post).

After I had a connection to internet with the RJ45 cable, I update the ntfs-3g and the system as referred in the installation post, but the error persist and I cannot access Windows.

I have checked the UEFI boot with F2 at the boot and it is in legacy mode. When in legacy, and with the menuentry option in grub.cfg, the error that gives trying to access Windows is invalid signature.

If you change the boot to UEFI mode, appears a blue screen and can’t surpass the boot in any way.

I will give more info to help you to help me. I will appreciate your comments because I am stuck.

Thanks in advance.


I enclose the lsblk

for additional info