overlay_merge(9)

💅 overlay_merge(9) — like, the manual page, but make it make sense 🦋

okay so bestie, welcome to overlay_merge from the Kernel API Manual — yes that manual, the kernel one, don't panic, we got this 💖

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✨ NAME ✨

overlay_merge — merges an overlay right into its base device tree, that's the whole gig 👑

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🌸 SYNOPSIS 🌸

int overlay_merge (void *fdt , void *fdto );

(no cap, that spacing is literally how it's written, i don't make the rules 💅)

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🎀 ARGUMENTS 🎀

• fdt — the base Device Tree blob, the main character 🌈
• fdto — the device tree overlay blob, the guest star showing up to merge into the main character's storyline 🦋

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💜 DESCRIPTION 💜

so overlay_merge merges an overlay into its base device tree. that's it, that's the function 💖

but like, context, because iykyk: this is the next to last step in the device tree overlay application process. at this point all the phandles have already been adjusted and resolved (slay ✨), and all that's left is for you to just merge the overlay into the base device tree. it's giving final boss but make it chill 🎀

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🔥 RETURN 🔥

• 0 on success — iconic, we love a clean win 👑
• Negative error code on failure — not the vibe, but at least it tells you 😭

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🫶 SEE ALSO 🫶

kernel file ./scripts/dtc/libfdt/fdt_overlay.c — that's where the magic lives, go look 🧚

and the whole friend group, fr fr:

• overlay_get_target_phandle(9)
• overlay_phandle_add_offset(9)
• overlay_adjust_node_phandles(9)
• overlay_adjust_local_phandles(9)
• overlay_update_local_node_references(9)
• overlay_update_local_references(9)
• overlay_fixup_one_phandle(9)
• overlay_fixup_phandle(9)
• overlay_fixup_phandles(9)
• overlay_adjust_local_conflicting_phandle(9)
• overlay_update_node_conflicting_references(9)
• overlay_update_local_conflicting_references(9)
• overlay_prevent_phandle_overwrite_node(9)
• overlay_prevent_phandle_overwrite(9)
• overlay_apply_node(9)
• overlay_symbol_update(9)

like, that's the whole group chat, every single one of them 💀

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okay that's the page bestie, hope it ate 🍓 this one came out of ./scripts/dtc/libfdt and it's dated October 2026 — talk about a main character timestamp ⭐ bye luv u 💜