[puddly]

As a test, I was able to quickly port OpenThread RCP + Ziggurat firmware to the nRF52840 dongle. You don't need this to run Ziggurat (host mode with stock OpenThread RCP firmware will always work), it's just a test to see where the embedded stack fits and how well it performs on-chip.

[puddly]

I migrated my home network to this embedded firmware. No major issues.

I think APS ACKs are a little sluggish, I experienced this a few years ago when I last tried the nRF52840. Will require a bit more investigation.

[Copilot]

🔵 Needs a closer look

The unsafe heap allocator and panic retention depend on linker-defined RAM boundaries and bootloader reset behavior that require a target link map and on-device validation unavailable in this review.

No open issues 🎉

What changed in this PR

Adds an experimental nRF52840 Dongle firmware port combining OpenThread RCP with the embedded Ziggurat stack. This provides an on-chip alternative for evaluation without changing support for host mode with stock RCP firmware.

Changes:

• Adds firmware build, linking, and USB DFU packaging for the nRF52840 Dongle.
• Introduces the nrf52 Rust platform feature with a dedicated heap allocator.
• Extends shared glue with Nordic reset reporting and support for newer OpenThread AES-CCM APIs.

File	Description
firmwares/​nrf52840/​ziggurat.cmake	Links the Rust stack and configures Nordic glue and system resets.
firmwares/​nrf52840/​ziggurat_vendor_hook.cpp	Includes both shared glue sources through the vendor hook.
firmwares/​nrf52840/​build.sh	Builds the combined firmware and generates a USB DFU package.
firmwares/​nrf52840/​.gitignore	Excludes generated firmware build artifacts.
firmwares/​glue/​ziggurat_glue.cpp	Adds Nordic platform support and newer AES-CCM API compatibility.
crates/​ziggurat-ot/​src/​lib.rs	Adds Nordic feature validation, critical sections, and heap initialization.
crates/​ziggurat-ot/​Cargo.toml	Defines the nrf52 feature and allocator dependency.
crates/​ziggurat-ot/​Cargo.lock	Locks the allocator and its transitive dependencies.

_{Review effort: Balanced}