Embedded C Developer – OpenWrt / OpenSync / WiFi

Title: Embedded C Developer – OpenSync/OpenWrt WiFi Router with Cellular BackupLocation: Englewood, CO(Onsite)Type: Contract (W2 Only)Job Description:We're looking for an Embedded C Developer to work on next-generation residential gateway platforms that combine DOCSIS/fiber WAN connectivity with LTE/5G cellular backup. You'll be developing and maintaining firmware on OpenWrt-based hardware running the OpenSync framework, with direct impact on millions of deployed customer premises equipment (CPE).Responsibilities• Design, develop, and debug embedded C software for Linux-based residential gateway platforms (ARM/MIPS SoC)• Develop and maintain OpenSync managers — event-driven daemons that interact with OVSDB for cloud-managed configuration and state reporting• Implement and optimize LTE/5G cellular failover and fallback logic including modem management, route arbitration, and WAN healthchecks• Develop LED state machine logic to provide accurate device status indication across complex multi-WAN scenarios• Interface with cellular modems via AT commands, QMI/MBIM, USB, and PCIe (MHI) protocols• Work with WiFi drivers (Qualcomm/Broadcom/Atheros) for 2.4GHz, 5GHz, and 6GHz radio configuration• Debug kernel-level issues including PCIe enumeration, USB device management, network driver crashes, and kernel panics• Implement and maintain secure communication channels using TLS with mutual authentication and tunneling protocols• Analyze and resolve field issues using device logs, crash dumps, and remote diagnostics• Develop init scripts, UCI configuration handlers, and persistent storage management for OpenWrt• Write unit tests and participate in code reviews via GitLab merge requests• Collaborate with hardware teams, QA, cloud platform engineers, and service provider partnersRequired Skills• 5+ years of embedded C development on Linux-based platforms• Strong proficiency in C programming — pointers, memory management, IPC, event-driven architectures• Experience with OpenWrt build system, package management, UCI configuration, and JFFS2/SquashFS overlay filesystems• Familiarity with OpenSync or similar cloud-managed CPE frameworks (OVSDB, protobuf, MQTT telemetry)• Experience with cellular modem integration — AT commands, QMI, network interface management (rmnet/wwan)• Strong understanding of Linux networking — routing tables, metrics, netfilter, bridge interfaces, IPv4 and IPv6 dual-stack, neighbor discovery, DHCPv4/DHCPv6, SLAAC, and prefix delegation• Understanding of TLS handshake with mutual authentication using X.509 certificates, certificate chain validation, and secure provisioning• Knowledge of security and tunneling protocols — GRE tunneling, IPsec, VPN overlays, and secure encapsulation for cloud-managed traffic• Experience with event loop frameworks (libev, libuv, or similar)• Proficiency with debugging tools — GDB, strace, tcpdump, kernel logs, serial console• Familiarity with Git, GitLab CI/CD, cross-compilation toolchains• Understanding of WiFi standards (802.11ax/be) and wireless driver configuration