Add operating system to my grub linux

I have one problem with my linux because my grub only recognize my two operating system but not the third operating system. I have a Windows 10 and two Windows 7 installations and my two windows 7 share the same MBR. So when I update my grub only recognize two systems as shown below.

https://i.stack.imgur.com/JIY2x.png

The output when i use sudo fdisk -l:

https://i.stack.imgur.com/I6BeDl.png

The content of my grub:

Code:

---

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
if [ "${next_entry}" ] ; then
  set default="${next_entry}"
  set next_entry=
  save_env next_entry
  set boot_once=true
else
  set default="0"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}
function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

if [ x$feature_default_font_path = xy ] ; then
  font=unicode
else
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  51bb3bc0-19fe-4105-8ce4-068c603088e8
else
  search --no-floppy --fs-uuid --set=root 51bb3bc0-19fe-4105-8ce4-068c603088e8
fi
    font="/usr/share/grub/unicode.pf2"
fi

if loadfont $font ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=es_ES
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=30
else
  if [ x$feature_timeout_style = xy ] ; then
    set timeout_style=menu
    set timeout=5
  # Fallback normal timeout code in case the timeout_style feature is
  # unavailable.
  else
    set timeout=5
  fi
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod ext2
set root='hd0,msdos7'
if [ x$feature_platform_search_hint = xy ]; then
  search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  51bb3bc0-19fe-4105-8ce4-068c603088e8
else
  search --no-floppy --fs-uuid --set=root 51bb3bc0-19fe-4105-8ce4-068c603088e8
fi
insmod png
if background_image /usr/share/images/desktop-base/kali-grub.png; then
  set color_normal=white/black
  set color_highlight=black/white
else
  set menu_color_normal=cyan/blue
  set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
    set gfxpayload="${1}"
}
set linux_gfx_mode=
export linux_gfx_mode
menuentry 'Kali GNU/Linux' --class kali --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-51bb3bc0-19fe-4105-8ce4-068c603088e8' {
    load_video
    insmod gzio
    if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
    insmod part_msdos
    insmod ext2
    set root='hd0,msdos7'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  51bb3bc0-19fe-4105-8ce4-068c603088e8
    else
      search --no-floppy --fs-uuid --set=root 51bb3bc0-19fe-4105-8ce4-068c603088e8
    fi
    echo    'Cargando Linux 4.6.0-kali1-686-pae...'
    linux  /boot/vmlinuz-4.6.0-kali1-686-pae root=UUID=51bb3bc0-19fe-4105-8ce4-068c603088e8 ro initrd=/install/gtk/initrd.gz quiet
    echo    'Cargando imagen de memoria inicial...'
    initrd  /boot/initrd.img-4.6.0-kali1-686-pae
}
submenu 'Opciones avanzadas para Kali GNU/Linux' $menuentry_id_option 'gnulinux-advanced-51bb3bc0-19fe-4105-8ce4-068c603088e8' {
    menuentry 'Kali GNU/Linux, con Linux 4.6.0-kali1-686-pae' --class kali --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.6.0-kali1-686-pae-advanced-51bb3bc0-19fe-4105-8ce4-068c603088e8' {
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  51bb3bc0-19fe-4105-8ce4-068c603088e8
        else
          search --no-floppy --fs-uuid --set=root 51bb3bc0-19fe-4105-8ce4-068c603088e8
        fi
        echo    'Cargando Linux 4.6.0-kali1-686-pae...'
        linux  /boot/vmlinuz-4.6.0-kali1-686-pae root=UUID=51bb3bc0-19fe-4105-8ce4-068c603088e8 ro initrd=/install/gtk/initrd.gz quiet
        echo    'Cargando imagen de memoria inicial...'
        initrd  /boot/initrd.img-4.6.0-kali1-686-pae
    }
    menuentry 'Kali GNU/Linux, with Linux 4.6.0-kali1-686-pae (recovery mode)' --class kali --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-4.6.0-kali1-686-pae-recovery-51bb3bc0-19fe-4105-8ce4-068c603088e8' {
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_msdos
        insmod ext2
        set root='hd0,msdos7'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos7 --hint-efi=hd0,msdos7 --hint-baremetal=ahci0,msdos7  51bb3bc0-19fe-4105-8ce4-068c603088e8
        else
          search --no-floppy --fs-uuid --set=root 51bb3bc0-19fe-4105-8ce4-068c603088e8
        fi
        echo    'Cargando Linux 4.6.0-kali1-686-pae...'
        linux  /boot/vmlinuz-4.6.0-kali1-686-pae root=UUID=51bb3bc0-19fe-4105-8ce4-068c603088e8 ro single initrd=/install/gtk/initrd.gz
        echo    'Cargando imagen de memoria inicial...'
        initrd  /boot/initrd.img-4.6.0-kali1-686-pae
    }
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###

### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows 10 (en /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-2EC488C1C4888CB1' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos1'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  2EC488C1C4888CB1
    else
      search --no-floppy --fs-uuid --set=root 2EC488C1C4888CB1
    fi
    parttool ${root} hidden-
    drivemap -s (hd0) ${root}
    chainloader +1
}
menuentry 'Windows 7 (en /dev/sda2)' --class windows --class os $menuentry_id_option 'osprober-chain-9C02C65102C63056' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos2'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos2 --hint-efi=hd0,msdos2 --hint-baremetal=ahci0,msdos2  9C02C65102C63056
    else
      search --no-floppy --fs-uuid --set=root 9C02C65102C63056
    fi
    parttool ${root} hidden-
    chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/40_custom ###
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/40_custom.save ###
### END /etc/grub.d/40_custom.save ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###

---

How can I get all three OS's to show on my GRUB menu. In my case i want to include my sda6 partition that it was not included.