I had Windows 10 BIOS boot on one disk and Ubuntu BIOS boot on another disk. There was no problem booting either from grub.
I took advice and reinstalled Windows 10 with UEFI boot, as it refused to upgrade.
Now I can no longer boot Windows from grub on the BIOS disk. I would prefer to keep the Windows bootloader on the Windows disk
I tried chainloading Windows from an Ubuntu UEFI install on flash drive and that did not work either.
I have tried everything I could find on the Ask pages, nothing has worked.
Is it possible to chainload Windows 1909 release using grub?