How to add Windows 10 (legacy BIOS mode) in GRUB (Ubuntu 16, UEFI mode)?

Question

I need to add Windows 10 in GRUB.

Windows 10 I have installed in legacy BIOS mode. Similarly as in the screenshot:

Ubuntu 16 I have installed in UEFI mode.

$ [ -d /sys/firmware/efi ] && echo UEFI || echo BIOS
UEFI

I have two hard drives. Each operating system is installed on a separate hard drive.

$ sudo lsblk -o NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL
NAME                    FSTYPE        SIZE MOUNTPOINT LABEL
sda                                 465,8G            
├─sda1                  vfat         19,5G            RECOVERY
├─sda2                  ntfs        445,8G            Windows 10
└─sda3                  ntfs          450M            
sdb                                 232,9G            
├─sdb1                  vfat          512M /boot/efi  
├─sdb2                  ext2          488M /boot      
└─sdb3                  crypto_LUKS 231,9G            
  └─sda3_crypt          LVM2_member 231,9G            
    ├─ubuntu--vg-root   ext4          224G /          
    └─ubuntu--vg-swap_1 swap            8G            
      └─cryptswap1      swap            8G [SWAP]     
sr0                                  1024M            

Boot Info Script results.

On Windows, I run the following command:

C:\WINDOWS\system32>bcdboot C:\Windows /s C: /f uefi

I performed this command to create a bootable configuration.

In Ubuntu file /etc/grub.d/40_custom I added the following option:

if [ "${grub_platform}" == "efi" ]; then
menuentry "Windows 10 (BCD-UEFI configuration on system drive /dev/sda2)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    insmod search_fs_uuid
    insmod chain

    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  8684C04C84C04103
    else
      search --no-floppy --fs-uuid --set=root 8684C04C84C04103
    fi

    chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
fi

UUID of the partition labeled "Windows 10":

$ sudo blkid /dev/sda2
/dev/sda2: LABEL="Windows 10" UUID="8684C04C84C04103" TYPE="ntfs" PARTUUID="76692ca8-02"

The problem is booting Windows 10 does not progress further the Windows logo.