Access the EFI shell, potentially as "http://stackoverflow.com/a/70191983" describes, or via the UEFI.
Access startup.nsh as "https://forums.freebsd.org/threads/startup-nsh.79973/post-507479" describes, or via the UEFI.
Modify startup.nsh (this includes what the EFI automatically invokes) to include reset -c -fwui (as "https://sourceforge.net/p/refind/discussion/general/thread/05965d36c2/#ae25" describes) because that command invokes the interface for the firmware.
I have not evaluated this. It is mere consolidation of research.
Topic:
App & System Services
SubTopic:
Core OS
Tags: