Windows 8.1 and CentOS 7.2 dual boot installation does't work

Hi everyone. Last day I perform an installation of CentOS 7.2 following the advice of
http://www.tecmint.com/install-centos-7-dual-boot-with-windows-8-uefi-firmware/2/
and except of the yum updates because has no internet connection available it seem to finish well.

When I reboot the option of Windows was not present at grub. I decided to investigate more and I decided to add the menuentry in /boot/grub2/grub.cfg

menuentry ‘Windows Boot Manager (on /dev/sda2)’ --class windows --class os $menuentry_id_option ‘osprober-efi-6627-88B8’ {
insmod part_gpt
insmod fat
set root=‘hd0,gpt2’
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 6627-88B8
else
search --no-floppy --fs-uuid --set=root 6627-88B8
fi
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}

This is the code I introduced

Still with the code doesn’t work
I made yum update and the update related to the installation post of the ntfs-3g.
The fdisk -l
[root@localhost ~]# fdisk -l
WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.

Disk /dev/sda: 500.1 GB, 500107862016 bytes, 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: gpt

Start End Size Type Name

1 2048 1230847 600M Windows recover Basic data partition
2 1230848 1845247 300M EFI System EFI system partition
3 1845248 2107391 128M Microsoft reser Microsoft reserved partition
4 2107392 697292799 331.5G Microsoft basic Basic data partition
5 943052800 976773119 16.1G Windows recover Basic data partition
6 697292800 697294847 1M BIOS boot parti
7 697294848 697909247 300M Microsoft basic
8 697909248 943052799 116.9G Linux LVM

Disk /dev/mapper/centos-root: 20.0 GB, 20002635776 bytes, 39067648 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/centos-swap: 22.0 GB, 21999124480 bytes, 42967040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/centos-home: 83.5 GB, 83504398336 bytes, 163094528 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk /dev/mapper/docker-253:0-36195042-pool: 107.4 GB, 107374182400 bytes, 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 65536 bytes / 65536 bytes

and the lsblk
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 465.8G 0 disk
├─sda1 8:1 0 600M 0 part
├─sda2 8:2 0 300M 0 part
├─sda3 8:3 0 128M 0 part
├─sda4 8:4 0 331.5G 0 part
├─sda5 8:5 0 16.1G 0 part
├─sda6 8:6 0 1M 0 part
├─sda7 8:7 0 300M 0 part /boot
└─sda8 8:8 0 116.9G 0 part
├─centos-root 253:0 0 18.6G 0 lvm /
├─centos-swap 253:1 0 20.5G 0 lvm [SWAP]
└─centos-home 253:2 0 77.8G 0 lvm /home
loop0 7:0 0 100G 0 loop
└─docker-253:0-36195042-pool 253:3 0 100G 0 dm
loop1 7:1 0 2G 0 loop
└─docker-253:0-36195042-pool 253:3 0 100G 0 dm

and the blkid info is as follows

[root@localhost ~]# blkid
/dev/sda1: LABEL=“Recovery” UUID=“960424FC0424E0CB” TYPE=“ntfs” PARTLABEL=“Basic data partition” PARTUUID=“dc4324d8-5ae4-4bd8-badf-d2a24d112769”
/dev/sda2: LABEL=“ESP” UUID=“6627-88B8” TYPE=“vfat” PARTLABEL=“EFI system partition” PARTUUID=“36b61393-437c-4c7a-b614-f041a8eaf048”
/dev/sda3: PARTLABEL=“Microsoft reserved partition” PARTUUID=“3453d69a-ffa1-43ee-b5e0-c8969198b181”
/dev/sda4: LABEL=“Acer” UUID=“14962A9A962A7BFC” TYPE=“ntfs” PARTLABEL=“Basic data partition” PARTUUID=“752168b4-5ccd-4aa1-8bb3-311b92a54efc”
/dev/sda5: LABEL=“Push Button Reset” UUID=“80502DC2502DBFB0” TYPE=“ntfs” PARTLABEL=“Basic data partition” PARTUUID=“004656ff-ebca-4658-90a3-fc14e8ecb228”
/dev/sda6: PARTUUID=“6abb8a00-45c8-45df-a358-f4e7b908ce7a”
/dev/sda7: UUID=“9602fc59-e2b0-40f3-b952-053b10f5f0c3” TYPE=“xfs” PARTUUID=“7da9ee13-fb1d-464b-aea0-a5071508d3d3”
/dev/sda8: UUID=“UH8wOG-PdGb-6XT3-CiER-UI82-x7wc-hfEUJ8” TYPE=“LVM2_member” PARTUUID=“2494cf8c-ceab-40ab-9bb0-0f15af450fb2”
/dev/mapper/centos-root: UUID=“5666c5f5-395c-4d3d-9efc-3e332277e404” TYPE=“xfs”
/dev/mapper/centos-swap: UUID=“bf31fc9a-ace4-40ba-95ae-bb2b1d06f501” TYPE=“swap”
/dev/mapper/centos-home: UUID=“d8459aaf-b2fa-42cb-b7a8-20de60de64b3” TYPE=“xfs”
/dev/loop0: UUID=“a15f9f57-4328-4023-a7c1-bf693f467780” TYPE=“xfs”
/dev/mapper/docker-253:0-36195042-pool: UUID=“a15f9f57-4328-4023-a7c1-bf693f467780” TYPE=“xfs”

The windows option now appears but says invalid signature
The boot is in legacy. When I changed to UEFI mode, appears a blue screen and says unable to load system

Could any one help me to recover the windows 8.1 system and make work the dual boot as I intended?

Thanks a lot in advance

This may help you.

https://ask.fedoraproject.org/en/question/69675/grub2-windows-entry-throws-invalid-signature/