USB Keyboard emulator for root level / EFI BIOS on a mac

Hello everyone,

I'm having problems with my Leonardo based keyboard emulator.

It's working fine inside MacOS but not at the FileVault login screen (which comes before my OS is even loaded)
I'm using a modified USB Core/Description that only loads the HID profile, so no serial device connection is active.
I tried to change the vendor and product ids to match the working Apple Keyboard without success...
This is probably related to the drivers on the Mac side, but how can I make the Leonardo act even more like a keyboard...?

Thanks for any help...

That is of course, why it is Apple!

For anyone who is interested. I solved the problem by using NicoHoods HID project library that offers a boot mode. That is working great on a mac prior booting.