Windows 8.1 not booting from grub menu option after updating grub

Here is some information

root@kali:~# grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found background image: /usr/share/images/desktop-base/desktop-grub.png
Found linux image: /boot/vmlinuz-4.0.0-kali1-amd64
Found initrd image: /boot/initrd.img-4.0.0-kali1-amd64
No volume groups found
Found Windows 8 (loader) on /dev/sda2
done
root@kali:~# parted -l
Model: ATA HGST HTS541010A9 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system Flags
1 32.3kB 1049kB 1016kB primary
2 1049kB 368MB 367MB primary ntfs
3 368MB 109GB 108GB primary ntfs
4 969GB 1000GB 31.3GB primary ext4 boot


Model: WD Elements 10B8 (scsi)
Disk /dev/sdb: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system Flags
1 1049kB 1000GB 1000GB primary ntfs boot





My /dev/sda2 is of only 350MB and
I have a another partition of 800GB in NTFS .Gparted shows it as UNALLOCATED but in Windows it works fine as a healthy drive.
There is a error when I select Win8 loader on GRUB menu.I will update it.