[U-Boot] boot a bios/uefi with x86_64, without grub

[Thierry Gayet]

Hi,

I am working with a board called "up board" (
http://www.aaeon.com/en/p/up-board-computer-board-for-professional-makers)
from aaeon.

This card is as tiny as a credit card or a raspberry pi running with a
x86_64 processor.

It buildin an UEFI BIOS and a MMC memory (no sdcard, no ssd, no sata, no
rom).

I know this is not really adapt to an embedded usage but i would like to
let my u-boot bootloader loading my gnu/linux kernel (using the bootefi
command) then my linux rootfs (generated by yocto) :

(UEFI / BIOS) -> (uboot uefi) -> (GNU/Linux kernel) --> (linux rootfs)

I do not want to use grub or grub uefi if possible.

My idea is to make a uefi partition on the eMMC memory.

I am looking for an uboot configuration i can use to compile my bootloader.

I have make tests with the u-boot-app.efi that i have compiled and set into
an efi paritiion ; i am booting into an usb key first. This is not working
and always stop at the uefi shell...

Maybe my u-boot-app.efi need to be signed ?

Is there a documentation that describe all steps required ?

Any help welcome in order to solve my use case. Thanks in advance.

Regards

Thierry