Senior Zephyr RTOS / Embedded Systems Engineer

Before You Apply

This is a Full-Time Employment opportunity. We are not considering B2B, freelance, consulting, or independent-contractor arrangements for this position.

This is a hands-on Zephyr RTOS platform-engineering role.

We need an engineer who can work inside and around Zephyr itself — close to the MCU, BSP, drivers, interrupts, memory, timing, boot flow, and hardware.

If your experience is primarily developing applications on top of an RTOS without hands-on experience with Zephyr internals, BSP/board bring-up, DeviceTree/Kconfig, device drivers, MCU architecture, or low-level hardware/software debugging, this role will not be the right match.

About L4B Software

L4B Software develops secure, reliable operating-system platforms for embedded, regulated, and long-lifecycle products.

Our platforms include MediTUX OS (Embedded Linux), MedicDroid (Android/AOSP), and MediTUX-RT, our real-time operating-system platform for microcontroller-based systems.

Our engineering processes operate within an ISO 13485-certified quality management system, with software lifecycle and risk-management processes aligned with IEC 62304 and ISO 14971.

About the Role

We are looking for a Senior Zephyr RTOS / Embedded Systems Engineer to help build and evolve MediTUX-RT, L4B's real-time operating-system platform for embedded and medical-device applications.

This is a Senior Individual Contributor role requiring substantial technical ownership.

You will work directly with Zephyr, MCU platforms, BSPs, drivers, interrupts, memory, timing, boot processes, firmware, and hardware integration, while collaborating with embedded, Linux, cybersecurity, validation, and quality engineers.

What You'll Do

Develop, integrate, and maintain Zephyr RTOS-based embedded platforms.
Work directly with Zephyr internals, kernel configuration, Kconfig, DeviceTree, west, and the Zephyr build system.
Perform board bring-up and BSP development/integration for MCU-based hardware.
Develop, integrate, and debug device drivers and hardware interfaces.
Work with peripherals and buses including SPI, I2C, UART, CAN, GPIO, timers, ADC, PWM, and watchdogs.
Debug issues involving interrupts, concurrency, synchronization, scheduling, memory, timing, and hardware interaction.
Analyze and improve real-time behavior, determinism, latency, resource usage, and system reliability.
Work with bootloaders, firmware updates, flash layouts, and device startup flows.
Develop production-quality embedded C/C++.
Investigate complex problems using JTAG/SWD, GDB, logic analyzers, oscilloscopes, and hardware debugging tools.
Develop automated tests and platform-level validation.
Contribute to secure firmware design, including Secure Boot and secure update mechanisms where applicable.
Produce maintainable technical documentation and engineering evidence suitable for long-lifecycle and regulated products.
Collaborate with hardware, validation, cybersecurity, quality, and other platform-engineering teams.

What You Bring

Must Have

Strong professional experience in embedded systems and firmware development.
Significant hands-on experience with Zephyr RTOS.
Strong understanding of RTOS concepts including scheduling, threads, interrupts, synchronization/IPC, timers, memory management, concurrency, and real-time constraints.
Strong embedded C development skills; C++ experience is valuable.
Hands-on experience with MCU-based systems, ideally ARM Cortex-M.
Experience with board bring-up, BSPs, and low-level hardware integration.
Experience developing or debugging device drivers.
Practical experience with Zephyr DeviceTree and Kconfig.
Strong hardware/software debugging skills.
Ability to investigate problems across the complete stack — from software behavior through RTOS and drivers down to the hardware.
Ability to independently own and resolve complex platform-level technical problems.

Technical Experience We Value

Experience in several of the following areas would be particularly valuable:

Experience with medical-device, safety-critical, security-sensitive, or other regulated embedded products is a strong advantage, including exposure to IEC 62304, ISO 14971, IEC 61508, or comparable development environments.

What This Role Is Not

This is not primarily:

Embedded application development on top of an RTOS
Embedded Linux engineering
Android/AOSP engineering
Hardware design
Project management
People management

We need an engineer who can go deep into Zephyr, RTOS internals, MCU architecture, BSPs, drivers, and hardware/software interaction and independently solve difficult platform-level problems.

What Success Looks Like

You become a technical owner of significant parts of MediTUX-RT.

You can take a new MCU or board, understand what is required to support it, bring the platform up, integrate and debug the necessary components, and drive technical issues through to resolution.

When timing, memory, driver, interrupt, boot, or hardware-related problems occur, you can systematically diagnose them rather than treating the RTOS as a black box.

Most importantly, you help us build a reliable, secure, maintainable, testable, and production-grade Zephyr platform suitable for demanding and regulated embedded products.

Our Hiring Approach

We hire for demonstrated technical capability, relevant hands-on experience, problem-solving ability, and engineering ownership. A formal degree can be valuable, but equivalent practical experience is welcome where a degree is not essential to performing the work.

Sibiu, Romania | Remote | Full-Time Employment

No B2B, freelance, consulting, or independent-contractor arrangements.

If you have spent years working deep inside Zephyr and embedded systems — and enjoy solving difficult problems where software meets hardware — we would like to talk.