Once you have installed RebornOS, you may see that the Windows entry is not present in Grub. You can restore it by following the below steps on RebornOS:
ntfs-3gif not already present.
sudo pacman -S --needed os-prober ntfs-3g
os-proberto check if it recognizes Windows
sudo pacman -S --needed gedit sudo gedit /etc/default/grub
Uncomment/edit/add this entry:
Make sure that there is no
# before the entry.
Save the file and exit.
sudo grub-mkconfig -o /boot/grub/grub.cfg