[PATCH] boot: Add LEGACY_IMAGE_FORMAT to DISTRO_DEFAULTS

[Tom Rini]

On Tue, Aug 19, 2025 at 06:46:19PM +0100, Peter Robinson wrote:
> On Tue, 19 Aug 2025 at 18:44, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Tue, Aug 19, 2025 at 06:38:46PM +0100, Peter Robinson wrote:
> > > On Tue, 19 Aug 2025 at 16:35, Tom Rini <trini at konsulko.com> wrote:
> > > >
> > > > On Tue, Aug 19, 2025 at 04:33:07PM +0100, Peter Robinson wrote:
> > > > > On Tue, 19 Aug 2025 at 15:57, Tom Rini <trini at konsulko.com> wrote:
> > > > > >
> > > > > > On Tue, Aug 19, 2025 at 12:13:31PM +0100, Peter Robinson wrote:
> > > > > > > On Mon, 18 Aug 2025 at 17:51, Tom Rini <trini at konsulko.com> wrote:
> > > > > > > >
> > > > > > > > At this time there are still major Linux distributions which by default
> > > > > > > > boot using LEGACY_IMAGE_FORMAT type scripts. Add this option to
> > > > > > > > DISTRO_DEFAULTS to ensure these platforms can still boot.
> > > > > > >
> > > > > > > What is the legacy image format exactly? Does select make it non
> > > > > > > optional, can we use imply or similar here?
> > > > > >
> > > > > > In this case "legacy image format" is uImage-style images, rather than
> > > > > > FIT images. And no, we can't imply it because then we'd break Debian
> > > > > > (which doesn't boot on a handful of platforms now which do have
> > > > > > DISTRO_DEFAULTS but don't have this).
> > > > >
> > > > > The distro boot stuff, which if my memory servers, is what the
> > > > > DISTRO_DEFAULTS is used for, never used the uImage style kernels.
> > > >
> > > > The same uImage-style header is what's on top of a "boot.scr" type file.
> > >
> > > The distro default scripts never used that either, the whole point of
> > > them was to move away from manually crafted scripts and custom formats
> > > to boot a device.
> >
> > Maybe we're talking past each other now. If distro_bootcmd never would
> > have found /boot/boot.scr, erm, OK. But the resulting U-Boot image could
> > still be used by Debian (and I think others, perhaps armbian) that would
> > still rather write their own logic and set the bootcmd, and relied on a
> > set of standard features being enabled in any board.
> 
> The major concern I have here is not being able to turn it off for
> boards that are constrained, which is typically the older/smaller
> boards like BBone, Jetson Nano etc

Right. But the initial report here was for BBone :) Given the relative
few platforms that didn't already have this on, I'm not sure how much an
issue it is. But that gets back to the trade-offs question too. If
you're super size constrained and can't find something else too to do,
then it's time to manage things more directly.

-- 
Tom
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