Hi Kory,

Am 17.02.2026 um 10:36 schrieb Kory Maincent [off-list ref]:

On Tue, 17 Feb 2026 09:58:04 +0100
H. Nikolaus Schaller [off-list ref] wrote:

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Hi Kory,

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Am 16.02.2026 um 16:11 schrieb Kory Maincent [off-list ref]:

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Am 12.02.2026 um 16:26 schrieb Kory Maincent (TI)
[off-list ref]:

Allow overlays to be applied to any DTB. This adds around ~40% to the
total size of the DTB files on average.    

Yes, I will move on to this solution for now to avoid too many complaints
about the devicetree size increases.  

I have done some experimentation with this patch (on top of v6.19 and our
private defconfig) but could not find any DTB size increase.

Does it require another patch or CONFIG change?

No, but maybe you had already the "DTC_FLAGS=-@" option enabled while building
you image.
This options add the "__symbols__" node listing the symbols to the built
devicetree:
$ fdtdump arch/arm/boot/dts/ti/omap/am335x-bonegreen-eco.dtb 2>/dev/null | grep symbols

Yes, indeed there is a __symbols__ node in all .dtb I have checked.

With make V=1 (on v6.19.0 + some local extensions) I see

./scripts/dtc/dtc -o arch/arm/boot/dts/ti/omap/am335x-bonegreen.dtb -b 0 -iarch/arm/boot/dts/ti/omap/ -i./scripts/dtc/include-prefixes -Wno-interrupt_provider --symbol -Wno-unique_unit_address -Wno-unit_address_vs_reg -Wno-avoid_unnecessary_addr_size -Wno-alias_paths -Wno-graph_child_address -Wno-simple_bus_reg   -Wno-unique_unit_address -Wno-unit_address_vs_reg -Wno-avoid_unnecessary_addr_size -Wno-alias_paths -Wno-graph_child_address -Wno-interrupt_map -Wno-simple_bus_reg   -d arch/arm/boot/dts/ti/omap/.am335x-bonegreen.dtb.d.dtc.tmp arch/arm/boot/dts/ti/omap/.am335x-bonegreen.dtb.dts.tmp

So --symbol is already included, even without your patch.

With your patch I see:

./scripts/dtc/dtc -o arch/arm/boot/dts/ti/omap/am335x-bonegreen.dtb -b 0 -iarch/arm/boot/dts/ti/omap/ -i./scripts/dtc/include-prefixes -@ -Wno-interrupt_provider --symbol -Wno-unique_unit_address -Wno-unit_address_vs_reg -Wno-avoid_unnecessary_addr_size -Wno-alias_paths -Wno-graph_child_address -Wno-simple_bus_reg   -Wno-unique_unit_address -Wno-unit_address_vs_reg -Wno-avoid_unnecessary_addr_size -Wno-alias_paths -Wno-graph_child_address -Wno-interrupt_map -Wno-simple_bus_reg   -d arch/arm/boot/dts/ti/omap/.am335x-bonegreen.dtb.d.dtc.tmp arch/arm/boot/dts/ti/omap/.am335x-bonegreen.dtb.dts.tmp

Here we have -@ and --symbol (synonyms for dtc).

Well, I finally could trace it down to a malicious infection of our LetuxOS tree
by some ODROID kernel patch to scripts/Makefile.lib (0ac84640f12c). That patch
globally modifies the DTC_FLAGS mechanism and permanently adds --symbol instead of adding
-@ in the arch/board specific Makefile like you propose here.

So now I know why I didn't see any increase in size (because it was never reduced).

With removing this I now get 67179 bytes as default for am335x-bonegreen.dtb.
And with your patch I get (back) to 94260 bytes so I can confirm a 40.3% increase.

Please proceed as planned (I don't think it necessarily has to be limited to
motherboards with an expansion card system, although that would be a good
indication of its usefulness), and thank you for bringing our local issue
to my attention.

BR and thanks,
Nikolaus