[U-Boot] x86: Stuck trying to build a non-qemu EFI payload

[Stoppa, Igor]

Hi,
I have verified that I can reproduce a workign build of  U-Boot as
x86-64bit EFI payload for Qemu: I can boot it, interact with various
filesystems of both real and emulated disks, etc.


Now I would like to build and boot it for a real board, still as EFI payload.

The docs/README.efi file states:

> U-Boot is packaged up and loaded in its entirety by EFI. Once
> started, U-Boot changes to 32-bit mode (currently) and takes over the
> machine. You can use devices, boot a kernel, etc.

My test device is a a D4250WYK NUC with a 4th generation Core i5
Haswell processor.
I tried booting it with an USB stick that I prepared and tested with qemu.
The build is based on the qemu-x86_defconfig, plus the EFI settings
needed for generating a 64 bit payload.

On qemu I can reach the U-Boot shell and run commands, however on the
NUC it stops at
the message "U-Boot EFI Payload", which is printed by the stub.

The stub is 64bit and the fact that I can see it printing anything
makes me infer that the word-size should not be the problem.

But I suspect I'm skipping some necessary step.

For example: does "takes over the machine" mean that (apart from the
settings specific to EFI) I should configure U-Boot like for a bare
build?

Or should I include some binary blob, still like for bare mode?

-- 
thanks, igor