[PATCH 1/2] distro_bootcmd: Add support for customizable find_distro_rootpart

[Kory Maincent]

On Tue, 4 Nov 2025 10:38:16 -0600
Tom Rini <trini at konsulko.com> wrote:

> On Tue, Nov 04, 2025 at 10:29:16AM +0100, Kory Maincent wrote:
> > On Mon, 3 Nov 2025 10:19:05 -0600
> > Tom Rini <trini at konsulko.com> wrote:
> >   
> > > On Mon, Nov 03, 2025 at 05:16:30PM +0100, Kory Maincent wrote:  
> > > > On Mon, 3 Nov 2025 11:52:25 +0100
> > > > Kory Maincent <kory.maincent at bootlin.com> wrote:
> > > > > > >        
> > > > > > 
> > > > > > How about moving to standard boot and look at this there?      
> > > > > 
> > > > > Ok, I will take a look at it.    
> > > > 
> > > > There is a custom nand boot target [1], and I have not any am335x board
> > > > with nand memory to test it. I am afraid to break it during the update
> > > > to bootstd. Not sure we can accept that. What do you think?
> > > > 
> > > > [1]https://elixir.bootlin.com/u-boot/v2025.10/source/include/configs/am335x_evm.h#L27
> > > >    
> > > 
> > > I think we can risk it. I'd even be OK with not migrating that portion
> > > and letting anyone still using those platforms, with NAND only, to just
> > > use a custom boot command instead as I have strong doubts there's anyone
> > > doing anything other than that currently.  
> > 
> > Ok.
> > 
> > Small questions related to standard boot:
> > Why do we have a lot of bootmeth selected by default like
> > BOOTMETH_EFILOADER, BOOTMETH_EFI_BOOTMGR, BOOTMETH_VBE ..., but
> > BOOTSTD_DEFAULTS not selected by default? Shouldn't it be the contrary?  
> 
> Hard to say. We got stuck on trying to find the right balance between
> features and size growth.

I still think we should disable these as default, moreover they are run first
in the bootstd process as they are global bootmeth.

> > Moreover it is explicitly described that global bootmeth can be slow:
> > https://elixir.bootlin.com/u-boot/v2025.10/source/doc/develop/bootstd/overview.rst#L103
> > 
> > The bootmeths environment variable is never read.
> > Changing this environment in the prompt allows to change the bootmeth order
> > thanks to this callback:
> > https://elixir.bootlin.com/u-boot/v2025.10/source/boot/bootmeth-uclass.c#L459
> > But if we set bootmeths in the board environment it doesn't work at all.
> > Is it intended?  
> 
> Standard boot is still in development. We're still in the process of
> getting more SoCs migrated and in turn finding and fixing the rough
> spots. Global boot meths have changed a bit since v2025.10 as part of
> hopefully addressing the feedback Andre P. had as part of migrating
> sunxi, but I think there's still the ordering half of his concerns to be
> figured out.

Ok thanks for your replies.

Other question: Is it possible to not add the environment to SPL image using
the new text environment format. I have tried to update am335_evm board to it
but I got a SPL too big error.
I have tried to add "#if !defined(XPL_BUILD)" but it is not working.
It seems the same generated environment file is used for all images.
I still haven't found were it is included in the build of the SPL image. 

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com