How to add Windows XP to GRUB2 menu

Question

I have a Dell Dimension 5150 with a Pentium D 820 (I know it's outdated but I received this from a friend as a Christmas gift.)

I have 2 hard disks in this desktop:

1. A 500GB 2.5' laptop HDD with Clover EFI installed (GPT BIOS Setup)

2. A 80GB 3.5' desktop HDD (normal MBR BIOS Setup)

Partition layout

Laptop HDD

sda1: Ubuntu MATE 16.04
sda2: Windows 10
sda3: Phoenix OS
sda4: DATA (Backup Storage Partition)
sda5: PARTIMG (Partition Image Storage)
sda6: ESP (EFI System Partition)

(I previously used a laptop and all my data is in there, but it died and this hard disk still can be used.)

Desktop HDD

sdb1: Dell System Utility (OEM Partition)
sdb2: Windows XP SP3 Home Edition
sdb3: Ubuntu XFce 18.04

How do I add Windows XP that is located on the second HDD's second partition to Ubuntu MATE 16.04 LTS's GRUB2 menu entry?

What I have tried:

1. insmod part_msdos
   insmod ntfs
   set root=(hd1,msdos2)
   chainloader +1
   error: Invalid EFI file path
   

2. insmod part_msdos
   insmod ntfs
   set root=(hd1,msdos2)
   chainloader /ntldr
   error: cannot load image
   

3. insmod part_msdos
   insmod ntldr
   insmod ntfs
   ntldr (hd1,msdos2)/ntldr
   error: ntldr.mod not found
   

4. insmod part_msdos
   insmod chain
   drivemap hd0 hd1
   chainloader (hd1,msdos2)+1
   error: drivemap command not found
   

5. insmod part_msdos
   insmod ntfs
   insmod search_fs_uuid
   search --fs-uuid --set=root --hint-bios=hd1,msdos2 --hint-efi=hd1,msdos2 --hint-baremetal=ahci1,msdos2 2ABF87DC395CFC02
   drivemap (hd1,msdos2) (hd0,msdos1)
   chainloader /ntldr
   error: cannot load image
   

What I have observed:

I did try if it can read the NTFS partition. It can read it without any problem. ls (hd1,msdos2)/ returns a bunch of files on the hard drive including the boot files (boot.ini, ntldr, AUTOEXEC.COM)

drivemap is only available in i386-pc package and not x86_64-efi package

It isn't the boot files problem as it boots normally if I disconnect the first hard drive (It boots into Windows XP normally).

os-prober and update-grub doesn't detect Windows XP partition (even if it's mounted). It only detects the first partition (Dell System Utility) on the second drive.