Yocto migration meta-barebox -> walnascar

[Ahmad Fatoum]

Hello Konstantin,

On 1/6/26 11:12 AM, Konstantin Kletschke wrote:
> On Tue, Jan 06, 2026 at 10:52:53AM +0100, Marco Felsch wrote:
> 
>> Which barebox version do you use?
> 
> It should be 2025.02.0.
> I switched to walnascar and this should be the part used:
> https://git.yoctoproject.org/poky/tree/meta/recipes-bsp/barebox?h=walnascar
> 
>> Ahmad added the support for a single barebox binary:
>>  - https://lore.barebox.org/barebox/20250422052635.3423961-1-a.fatoum@pengutronix.de/
>>
>> IIRC the purpose of the patchset was exactly to fulfill an easier Yocto
>> integration since the beaglebone is one of the oe-core real test hw.
> 
> That's is very interesting.
> What I did not get, yet:
> So we can keep our partition scheme, the CPUs bootloader is searching
> hardcoded for partition table -> first vfat -> MLO.
> Then barebox-am33xx-beaglebone.img is put there as MLO?

When enabled, the same barebox build generates two images:
barebox-am33xx-beaglebone-mlo.mmc.img -> MLO
barebox-am33xx-beaglebone.img -> barebox.bin

Both are placed in the VFAT.

>> Since the single image approach targets only the SD/MMC boot, the
>> standalone MLO image should be still possible.

I didn't test it on eMMC and I suspect it needs light tweaking to work
there. If you are happy to test, I can find some time later to send a patch.

>  Can this be switched on/off somewere in the yocto framework so the old
>  MLO/barebox.bin pair is genereated?

For your old setup, you will need two recipes. Just define your own
barebox.bb and barebox-pbl.bb recipes and inherit barebox in each and
use different configs. All the core logic is in a barebox.bbclass to
allow you to easily create your own recipes.

This allows you also to use a newer version than v2025.02.0 for example
v2025.09.1, which is going to be maintained for longer than just a month.

Cheers,
Ahmad

> 
> Regards
> Konstantin
> 
> 

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