Architecture & Planning
20 Aug
Senior Firmware Engineer, Zephyr RTOS and Connected Devices
Senior Firmware Engineer, Zephyr RTOS and Connected Devices (F/M) Location: Sibiu, Romania Work model: Hybrid / remote, one week per month on site Contract: Indefinite About our client Our client is an international group active in automotive electronics, with several thousand employees and with manufacturing and engineering sites in Europe, Asia and North America. The company develops and produces electronic and mechatronic components and control units for well known vehicle manufacturers, and also supplies a number of non automotive industrial markets. In Romania the group runs a combined manufacturing and engineering site in the Sibiu area. The local engineering team works on international series programmes together with colleagues at the other group locations, covering embedded software, electronics and system validation. This is not a support or outsourcing centre: what is developed here goes into series production. Why this role Full ownership of features from requirements and architecture through to implementation, test automation and performance optimisation. Modern embedded stack: Zephyr RTOS on ARM Cortex-M, BLE, UWB and NFC, secure boot and FOTA, rather than legacy maintenance work. Real hardware bring-up and debugging, not simulation only, with J-Link, logic analysers and oscilloscopes. Ownership of the CI/CD and automated test setup used to validate firmware on hardware. Hybrid arrangement with only one week per month on site in Sibiu, which makes the role workable from another city. The role Purpose of the role Design, build and ship production grade firmware for connected devices using Zephyr RTOS on ARM Cortex-M. Own features end to end, from requirements and architecture through implementation, test automation and performance optimization, with a strong emphasis on reliability, security and low power operation. Responsibilities Deliver embedded software across the full lifecycle: requirements, design, implementation, verification. Implement features across multiple subsystems (drivers, connectivity, power, security) and debug complex issues spanning firmware, hardware and toolchains. Work with devicetree and Kconfig, Zephyr drivers and subsystem APIs (Bluetooth, UltraWideBand, NFC, logging, shell, power management). Build and maintain automated tests (ztest, Twister) and CI/CD pipelines for firmware validation on real hardware. Perform hardware bring-up (boot, clocks, peripherals, memory maps) using J-Link, GDB, RTT and SWO. Work closely with hardware, QA and product teams to land features on schedule and at high quality. Contribute to secure boot and FOTA workflows and to production ready release practices. Must have qualifications Bachelor's degree in Automation, Computer Science, Telecommunications, Electronics or a related field. 5+ years building firmware for ARM Cortex-M devices, including at least 3 years hands on with Zephyr RTOS. Strong C and solid C++ familiarity, embedded design, device driver development (I2C/SPI/UART, GPIO/EXTI, ADC/DMA, timers). Zephyr essentials: devicetree, Kconfig, CMake/west, Zephyr SDK and toolchains, boards and overlays, subsystem integration. Connectivity experience with BLE (GAP/GATT) and at least one of UWB or NFC, proficiency with protocol sniffers and analyzers. Proficient in debugging and bring-up using J-Link, logic analyzers and oscilloscopes. Experience with CI/CD and automated test (ztest, Twister, HIL where applicable). Excellent written and spoken English. Nice to have Secure boot and updates (MCUboot, DFU/FOTA), secure storage, cryptography, key handling. Low power design (sleep states, timers, power management policies) and profiling methodologies. Knowledge of MISRA-C, static analysis and code review practices. Experience with Nordic nRF or similar SoCs, including Bluetooth controller and host stack integration. Python for tooling and test harnesses, scripting for build and test automation. Familiarity with Agile workflows and backlog ownership. Tools and ecosystem Build: west, CMake, Zephyr SDK, Ninja, cache strategies. Test: ztest, Twister, HIL, unit and integration testing. Debug and trace: J-Link, GDB, RTT and SWO, logic analyzer, oscilloscope. CI/CD: GitHub Actions, GitLab CI or Jenkins, artifact versioning and release tagging. Collaboration: code reviews, design documents, cross team communication. Confidentiality Applications are treated in strict confidence. The name of the company is disclosed to shortlisted candidates before any interview. Personal data is processed in line with GDPR and only for the purposes of this recruitment process. CP_JA_19/08/2026