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

[Bin Meng]

Hi Thierry,

On Tue, Jul 31, 2018 at 6:18 PM, Thierry Gayet
<thierry.gayet at klaxoon.com> wrote:
> 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 ?

No. Since you mentioned the x86 processor is 64-bit, it's hightly
possible that you have a 64-bit EFI BIOS. That means you cannot use
u-boot-app.efi with this EFI BIOS since u-boot-app.efi is 32-bit.

>
> Is there a documentation that describe all steps required ?
>
> Any help welcome in order to solve my use case. Thanks in advance.
>

You will need try efi-x86_payload64, and boot from there. Note
currently there are issues to boot Linux kernel from the U-Boot
payload.

Regards,
Bin