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Only 0.51% Zephyr — Zephyr Podcast #024

By February 27, 2026No Comments

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Episode Summary

  • FIDO2/CTAP2 Authenticator Subsystem RFC: Sirat, the contributor behind the recent biometrics API, has opened an RFC proposing a FIDO2/CTAP2 authenticator subsystem for Zephyr. The proposal includes headers with support for multiple transports (Bluetooth, NFC, USB) and key management. FIDO2 powers passwordless authentication dongles — very much embedded targets suited for Zephyr. Feedback welcome in the Discord security channel. This could also make a great Google Summer of Code project — now is the time for maintainers and students to propose GSoC ideas by the way. Related prior art: Google’s OpenSK, a FIDO authenticator PoC on an nRF52840 dongle that appears to have gone quiet.
  • Job Shout-Out — Focusrite / Adam Audio (Berlin): Adam Audio, a Berlin-based subsidiary of Focusrite, is hiring for a role explicitly calling for Zephyr and STM32/NXP experience. They maintain a public Zephyr fork. Always nice to see well-known companies openly looking for Zephyr expertise!
  • ARM Cortex-M Context Switch Rework: The long-running performance-focused redesign of ARM Cortex-M context switching appears close to completion. Started by Andy Ross ~a year ago and picked up by Sudan at ARM, this 34-commit effort shows ~60% improvement in z_swap. The old implementation remains behind a Kconfig option for fallback. With feature freeze about a month away, now is a great time to test.
  • FTP Client Merged + TFTP Server Incoming: The new FTP client mentioned last week is now merged with a shell-based sample. Hours later, someone submitted a TFTP server PR (in review). Zephyr’s network protocols suite keeps growing.
  • Interactive HTML Build Report: A new PR from Qualcomm proposes a build target generating an interactive HTML report combining RAM/ROM usage, Kconfig symbol details (source, visibility), device tree info, initialization levels, and more. These reports existed individually but this tool aggregates and visualizes them beautifully. Extensible by design — SBOMs could easily be added later.
  • West Serial Monitor: Espressif is proposing a west serial monitor command — a persistent serial console that survives reboots and flashing without crashing when the UART device momentarily disappears. Especially useful for ESP32 where the serial port is shared between programming and console. Likely to replace Espressif’s existing serial monitor extension.
  • Zephyr SDK 1.0 RC1 Tagged: The first release candidate of Zephyr SDK 1.0 has been tagged. Artifacts aren’t available yet, but v1.0 is progressing well. Follow-up: the Mac Intel target may need removal from some CI actions.
  • Zephyr Code Distribution Breakdown: Roy Jamil posted an interesting pie chart of Zephyr’s code distribution on LinkedIn. The kernel is only ~0.5%, with drivers at 38%, subsystems at 25%, and tests at ~20% (~500K test cases run weekly!). A great reminder that Zephyr is far more than “just an RTOS kernel.”
  • Raspberry Pi Pico: IPC Mailbox + PIO MIPI-DBI Driver: Two cool Pico contributions: an inter-processor mailbox driver enabling asymmetric multiprocessing on the dual-core Pico, and a MIPI-DBI display driver on the PIO cores. The PIO’s segmented SRAM and bus fabric allow independent memory access from the main CPUs — great for offloading protocol-heavy tasks like driving displays or NeoPixels.
  • New Boards: The WCH CH32V307V-EVT-R1 adds another ultra-cheap RISC-V MCU — these WCH chips are everywhere, and a dedicated maintainer has stepped up. The Waveshare ESP32-S3-RLCD-4.2 features a reflective LCD (no backlight, think Casio watch) — low-power yet ~30 FPS capable. Also: the VIEWE UEDX24320028E, another ESP32 board with LCD and buzzer.
  • New Shield: MikroElektronika Flash 5 Click: Support added for a Click shield with 128 MB of NAND flash. Many more MikroElektronika shields being added so probably a few more will get mentioned next week!
  • New Driver: ADE7978 Polyphase Energy Metering: A new driver for the Analog Devices ADE7978 polyphase energy metering front-end with integrated galvanic isolation. Supports three-phase plus neutral in star and delta configurations — ideal for energy meters and motor monitoring.
  • Native SX126x LoRa Driver Merged: Carlo Caione’s native LoRa driver for the Semtech SX126x series, previously mentioned as a PR, is now merged — replacing dependency on Semtech’s proprietary HAL.
  • New Driver: WIZnet W6100 Ethernet-over-SPI: A new driver for the WIZnet W6100 adds Ethernet over SPI to any general-purpose MCU. The chip has its own TCP/IP stack, but the driver uses Zephyr’s networking stack for more flexibility. A companion shield was also added.
  • Embedded World & 10-Year Anniversary Survey: Embedded World in Nuremberg is ~10 days away. The Zephyr 10-year anniversary survey results are being finalized — expect a deep dive in next week’s episode!