[CentOS] Dual boot C7 with Window 10

I have a laptop with windows 10.
I went into the Windows disk manager and shrunk the volume
to make room for C7. That worked.

I also changed the BIOS from secure boot to "both" (secure/legacy)

I installed C7, went fine. About the time it was done I realized I never
saw anything about "other" boot options (seems I saw that in the past).

Anyway sure enough, got done and C7 boots fine - no option there for
Windows.  I did searching and found I needed to add to the
/etc/grub.d/40_custom the following:
menuentry "Windows 10" {
    set root='(hd0,1)'
    chainloader +1
}

then re-run the grub2-mkconfig -o /boot/grub2/grub.cfg

I then rebooted and sure enough I got the menu item for "Windows 10"
however when I select it it does not boot.

How do I get Windows 10 to boot again ?

Thanks,

Jerry