{"schemaVersion":"jobsearcher.job.v1","id":"f5bb1cfb4aeb3b32e7ea6634","url":"https://jobsearcher.com/jobs/f5bb1cfb4aeb3b32e7ea6634","canonicalUrl":"https://jobsearcher.com/jobs/f5bb1cfb4aeb3b32e7ea6634","title":"Embedded C Developer","description":"Embedded C Developer – OpenSync/OpenWrt WiFi Router with Cellular BackupLocation: Englewood, CO - Onsite.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 reportingImplement and optimize LTE/5G cellular failover and fallback logic including modem management, route arbitration, and WAN healthchecksDevelop LED state machine logic to provide accurate device status indication across complex multi-WAN scenariosInterface with cellular modems via AT commands, QMI/MBIM, USB, and PCIe (MHI) protocolsWork with WiFi drivers (Qualcomm/Broadcom/Atheros) for 2.4GHz, 5GHz, and 6GHz radio configurationDebug kernel-level issues including PCIe enumeration, USB device management, network driver crashes, and kernel panicsImplement and maintain secure communication channels using TLS with mutual authentication and tunneling protocolsAnalyze and resolve field issues using device logs, crash dumps, and remote diagnosticsDevelop init scripts, UCI configuration handlers, and persistent storage management for OpenWrtWrite unit tests and participate in code reviews via GitLab merge requestsCollaborate with hardware teams, QA, cloud platform engineers, and service provider partnersRequired Skills:5+ years of embedded C development on Linux-based platformsStrong proficiency in C programming — pointers, memory management, IPC, event-driven architecturesExperience with OpenWrt build system, package management, UCI configuration, and JFFS2/SquashFS overlay filesystemsFamiliarity 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 delegationUnderstanding of TLS handshake with mutual authentication using X.509 certificates, certificate chain validation, and secure provisioningKnowledge of security and tunneling protocols — GRE tunneling, IPsec, VPN overlays, and secure encapsulation for cloud-managed trafficExperience with event loop frameworks (libev, libuv, or similar)Proficiency with debugging tools — GDB, strace, tcpdump, kernel logs, serial consoleFamiliarity with Git, GitLab CI/CD, cross-compilation toolchainsUnderstanding of WiFi standards (802.11ax/be) and wireless driver configurationTools & Technologies:Languages: C, Shell scripting (sh/bash), Python (test automation)OS/Platform: OpenWrt (Linux 5.x/6.x kernel), ARM Cortex-A53/A73Frameworks: OpenSync, OVSDB, libev, protobuf-c, jansson (JSON)Chipsets: Qualcomm IPQ, Broadcom BCM, Atheros/QCANetworking: iproute2, iptables/nftables, ovsdb-server, hostapd/wpa_supplicant, GRE, IPsecSecurity: OpenSSL/mbedTLS, X.509 certificates, mTLS, certificate managementCellular: Qualcomm QCM/SDX modems, MHI, qcserial, AT+QENG/AT+COPSProtocols: IPv4, IPv6, DHCPv4/v6, DNS, MQTT, GRE, TLS 1.2/1.3Build: Make, Kconfig, OpenWrt feeds, cross-compilation (musl/glibc)Debug: GDB, valgrind, serial console, logpull analysisVCS/CI: Git, GitLab, merge request workflowsNice to Have:Experience working directly with ISP/MSO/OEM partnersExposure to hardware bring-up and board support package (BSP) developmentExperience with Agile/Scrum in a firmware development contextFamiliarity with SCTE/DOCSIS standardsUnderstanding of TR-181 data model parameters for WAN management, WiFi configuration, and device monitoringExperience with GRE tunnel implementation for backhaul traffic in managed WiFi deploymentsWhat You'll Work On:Cellular failover/fallback state machines with sub-second transition handlingLED indication logic for multi-WAN connectivity statesModem health monitoring and subsystem restart/recoveryInternet reachability healthcheck frameworksCloud-managed device configuration and telemetry reporting via MQTTSecure cloud connectivity using mTLS with X.509 certificate-based mutual authenticationGRE tunnel management for cloud-redirected trafficFactory reset, firmware upgrade, and persistent storage managementIPv4/IPv6 dual-stack network configuration, routing, and failover across DOCSIS and LTE interfacesWiFi radio configuration and performance optimization across Qualcomm / Broadcom platformsKernel crash analysis and driver-level bug resolutionTop Skills:Embedded C Development on Linux/OpenWrt: C programming, Linux internals, debugging, IPC, event-driven designOpenSync/OpenWrt Platform Development: OpenSync Managers, OVSDB, UCI, MQTT, OpenWrt build systemLinux Networking & LTE/5G Cellular Integration: Routing, IPv4/IPv6, failover, QMI/MBIM, modem management, GRE/IPsecAdditional Details:Team size 8 Direct report - None Key Deliverables:","company":"Apolis","rawCompany":"apolis","city":"Englewood","state":"CO","isRemote":false,"isActive":true,"createdAt":"2026-09-11T07:54:02.617Z","occupations":[{"code":"15-1252.00","title":"Software Developers","slug":"software-developers"},{"code":"15-1299.08","title":"Computer Systems Engineers/Architects","slug":"computer-systems-engineers-architects"},{"code":"17-2061.00","title":"Computer Hardware Engineers","slug":"computer-hardware-engineers"}],"industries":[{"code":"541512","title":"Computer Systems Design Services","slug":"computer-systems-design-services"},{"code":"541511","title":"Custom Computer Programming Services","slug":"custom-computer-programming-services"},{"code":"517112","title":"Wireless Telecommunications Carriers (except Satellite)","slug":"wireless-telecommunications-carriers-except-satellite"}],"jobPosting":{"@context":"https://schema.org","@type":"JobPosting","title":"Embedded C Developer","description":"Embedded C Developer – OpenSync/OpenWrt WiFi Router with Cellular BackupLocation: Englewood, CO - Onsite.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 reportingImplement and optimize LTE/5G cellular failover and fallback logic including modem management, route arbitration, and WAN healthchecksDevelop LED state machine logic to provide accurate device status indication across complex multi-WAN scenariosInterface with cellular modems via AT commands, QMI/MBIM, USB, and PCIe (MHI) protocolsWork with WiFi drivers (Qualcomm/Broadcom/Atheros) for 2.4GHz, 5GHz, and 6GHz radio configurationDebug kernel-level issues including PCIe enumeration, USB device management, network driver crashes, and kernel panicsImplement and maintain secure communication channels using TLS with mutual authentication and tunneling protocolsAnalyze and resolve field issues using device logs, crash dumps, and remote diagnosticsDevelop init scripts, UCI configuration handlers, and persistent storage management for OpenWrtWrite unit tests and participate in code reviews via GitLab merge requestsCollaborate with hardware teams, QA, cloud platform engineers, and service provider partnersRequired Skills:5+ years of embedded C development on Linux-based platformsStrong proficiency in C programming — pointers, memory management, IPC, event-driven architecturesExperience with OpenWrt build system, package management, UCI configuration, and JFFS2/SquashFS overlay filesystemsFamiliarity 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 delegationUnderstanding of TLS handshake with mutual authentication using X.509 certificates, certificate chain validation, and secure provisioningKnowledge of security and tunneling protocols — GRE tunneling, IPsec, VPN overlays, and secure encapsulation for cloud-managed trafficExperience with event loop frameworks (libev, libuv, or similar)Proficiency with debugging tools — GDB, strace, tcpdump, kernel logs, serial consoleFamiliarity with Git, GitLab CI/CD, cross-compilation toolchainsUnderstanding of WiFi standards (802.11ax/be) and wireless driver configurationTools & Technologies:Languages: C, Shell scripting (sh/bash), Python (test automation)OS/Platform: OpenWrt (Linux 5.x/6.x kernel), ARM Cortex-A53/A73Frameworks: OpenSync, OVSDB, libev, protobuf-c, jansson (JSON)Chipsets: Qualcomm IPQ, Broadcom BCM, Atheros/QCANetworking: iproute2, iptables/nftables, ovsdb-server, hostapd/wpa_supplicant, GRE, IPsecSecurity: OpenSSL/mbedTLS, X.509 certificates, mTLS, certificate managementCellular: Qualcomm QCM/SDX modems, MHI, qcserial, AT+QENG/AT+COPSProtocols: IPv4, IPv6, DHCPv4/v6, DNS, MQTT, GRE, TLS 1.2/1.3Build: Make, Kconfig, OpenWrt feeds, cross-compilation (musl/glibc)Debug: GDB, valgrind, serial console, logpull analysisVCS/CI: Git, GitLab, merge request workflowsNice to Have:Experience working directly with ISP/MSO/OEM partnersExposure to hardware bring-up and board support package (BSP) developmentExperience with Agile/Scrum in a firmware development contextFamiliarity with SCTE/DOCSIS standardsUnderstanding of TR-181 data model parameters for WAN management, WiFi configuration, and device monitoringExperience with GRE tunnel implementation for backhaul traffic in managed WiFi deploymentsWhat You'll Work On:Cellular failover/fallback state machines with sub-second transition handlingLED indication logic for multi-WAN connectivity statesModem health monitoring and subsystem restart/recoveryInternet reachability healthcheck frameworksCloud-managed device configuration and telemetry reporting via MQTTSecure cloud connectivity using mTLS with X.509 certificate-based mutual authenticationGRE tunnel management for cloud-redirected trafficFactory reset, firmware upgrade, and persistent storage managementIPv4/IPv6 dual-stack network configuration, routing, and failover across DOCSIS and LTE interfacesWiFi radio configuration and performance optimization across Qualcomm / Broadcom platformsKernel crash analysis and driver-level bug resolutionTop Skills:Embedded C Development on Linux/OpenWrt: C programming, Linux internals, debugging, IPC, event-driven designOpenSync/OpenWrt Platform Development: OpenSync Managers, OVSDB, UCI, MQTT, OpenWrt build systemLinux Networking & LTE/5G Cellular Integration: Routing, IPv4/IPv6, failover, QMI/MBIM, modem management, GRE/IPsecAdditional Details:Team size 8 Direct report - None Key Deliverables:","datePosted":"2026-09-11T07:54:02.617Z","dateModified":"2026-09-11T07:54:02.617Z","hiringOrganization":{"@type":"Organization","name":"Apolis","sameAs":"https://jobsearcher.com"},"jobLocation":{"@type":"Place","address":{"@type":"PostalAddress","addressLocality":"Englewood","addressRegion":"CO","addressCountry":"US"}},"identifier":{"@type":"PropertyValue","name":"JobSearcher","value":"f5bb1cfb4aeb3b32e7ea6634"},"url":"https://jobsearcher.com/jobs/f5bb1cfb4aeb3b32e7ea6634"}}