[Testlist] I need Dual Legacy EFI help

[ToddAndMargo]

Dear Grub,

I have a Fedora 30 flash drive set up for dual booting
from Legacy or UEFI.  It need to be able to boot from any
and all computers.

It also have a bios_grub partition.

It booted perfectly from both under Fedora 29.

I have two qemu-kvm machines set up to test.  One with EFI bios
and one with Legacy bios.  Nether have a "compatibility mode"

So far, I can boot into EFI perfectly.

Legacy, I get a Grub> prompt

Remaking grub.cfg, I get

   # grub2-mkconfig -o /boot/grub2/grub.cfg
   Generating grub configuration file ...
   Adding boot menu entry for EFI firmware configuration
   done

Uhhhhh.. I wanted legacy, not EFI.

How do I trick grub2-mkconfig to make me a Legacy boot
when I am booted into EFI?

Many thanks,
-T


My procedure (for Fedora 29):

UEFI.BIOS.Dual.Boot.txt:

References that stink:
    https://forums.linuxmint.com/viewtopic.php?t=223015
    https://bl.ocks.org/gdamjan/05b799162e4b3e97a30d37a89fed0fa8

https://forum.level1techs.com/t/configure-grub-to-boot-legacy-and-uefi/129382


Requirements:
   Fedora 29

   Before installing, gparted:
      Wipe the target disk

      create a partition table as GPT

      create a first partition as
          1 Meg
          unformatted
          set the partition flag to "bios_grub"

   Install Fedora 29 from a UEFI machine:
      "/home" was removed at installation and moved into "/"

--->>>   PRESUMED !!!   <<<---
      The machine was install and booted from UEFI
      The machine is mounted as /dev/sda


Install the legacy BIOS boot loader:

Boot into fedora on UEFI

only installs 3 files
# dnf reinstall grub2-pc

create the BIOS .cfg file
# grub2-mkconfig -o /boot/grub2/grub.cfg

Note: if this complains, you forgot to create the partition above
# grub2-install --removable --recheck --target=i386-pc 
--boot-directory=/boot /dev/sda