Suggest to use MX/antiX LiveUSB Boot Rescue feature, which might do what you want to use it for: Find any attached EFI-/legacy grub loader/grub menus +plus WinOS loader and boot into.
@fehlix I have dd'ed MX 19.4 , and enabled secure boot . Then, boot rescue menus can't detect any EFI bootloader. (it just shows "***Secure Boot Restrictions***" and no bootloaders detected)
But, my customized version (using LM's grub and modules) can detect EFI bootloaders (it just shows some secure boot errors, but they can be ignored)
Also the MX exfat GRUB module shows "Secure boot forbids loading ........." error, and can't detect exfat partitions (I decided to switch to NTFS)
I think that is because some MX GRUB modules aren't signed for "secure boot" , while LM's GRUB modules are signed.