TECHNOLOGY — Technology

Embedded Linux & BSP Development

Custom Linux distributions, board support packages, and RTOS integration for ARM, RISC-V, and x86 platforms. Yocto and Buildroot expertise with production-grade OTA, secure boot, and long-term maintenance.

OVERVIEW

Production-Ready Linux for Embedded Hardware

Every modern embedded product needs a software platform — a custom Linux distribution stripped to essentials, optimized for boot time and resource usage, secured for field deployment, and maintainable for the product's 10-15 year lifecycle. Promwad builds these platforms using Yocto Project and Buildroot, with full BSP development for custom hardware.

Our embedded Linux practice covers the full stack from bootloader (U-Boot, UEFI) through kernel configuration and driver development to userspace application frameworks. We integrate real-time domains (FreeRTOS, Zephyr, QNX) for applications requiring deterministic timing alongside Linux. Every platform includes OTA update capability, secure boot chain, and automated build/test infrastructure.

Custom Yocto Project distributions: layer architecture, recipe development, machine configuration
Buildroot-based minimal systems for resource-constrained platforms
BSP development: bootloader, kernel, device tree, driver development for custom hardware
OTA update systems: SWUpdate, RAUC, Mender with A/B partitioning and secure rollback
Secure boot chain: TPM 2.0 root of trust, hardware-backed key storage, dm-verity
RTOS integration: FreeRTOS, Zephyr, QNX alongside Linux (AMP or hypervisor)
Boot time optimization: sub-2-second cold boot for automotive and consumer applications
Long-term maintenance: CVE monitoring, kernel LTS tracking, automated security patching
ANONYMIZED PROJECTS

Selected Embedded Linux Projects

Yocto BSP for Automotive Infotainment Platform

Built a custom Yocto distribution for an automotive Tier-1's next-generation infotainment system on NXP i.MX 8QuadMax. Integrated AGL (Automotive Grade Linux) application framework, Wayland/Weston compositor with GPU acceleration, and A/B OTA via SWUpdate. Achieved 3.2-second cold boot to first UI frame.

OUTCOMEPassed ASPICE CL2 software process audit. Adopted by OEM for 3 vehicle platforms.

Industrial Gateway Linux Platform

Developed a Buildroot-based Linux platform for an industrial IoT gateway on TI AM6254. Supports IO-Link, Modbus TCP, MQTT, and OPC UA protocols simultaneously. Integrated Docker containerization for customer application deployment. SWUpdate OTA with delta updates to minimize bandwidth over cellular connections.

OUTCOMEBoot time under 4 seconds. 8-year CVE maintenance contract. 5,000+ units deployed.

RISC-V Linux Bring-Up for Semiconductor Startup

Performed full Linux bring-up on a custom RISC-V SoC for a European semiconductor startup. Ported U-Boot, mainlined device tree bindings, developed custom peripheral drivers (SPI, I2C, UART, PCIe), and built a Yocto BSP layer for customer distribution. Contributed upstream kernel patches.

OUTCOMEFirst Linux boot achieved in 6 weeks. BSP delivered to 12 early-access customers.

Client identities changed. Methodologies and outcomes are real.

ENGINEERING STACK

Embedded Linux Stack

Build Systems
Yocto Project (Poky, meta layers), Buildroot, OpenEmbedded, AGL (Automotive Grade Linux), ELBE for Debian-based embedded
Architectures
ARM Cortex-A53/A55/A72/A76, ARM Cortex-R5/R52, ARM Cortex-M4/M7/M33, RISC-V (RV64GC), x86-64 (Intel Atom, AMD Ryzen Embedded)
RTOS & Hypervisors
FreeRTOS, Zephyr, QNX, VxWorks, Xen hypervisor for mixed-criticality, Jailhouse partitioning hypervisor
OTA & Security
SWUpdate, RAUC, Mender, OSTree. TPM 2.0, ARM TrustZone, OP-TEE, dm-verity, secure boot with HAB (NXP) or eFuse (TI)
Connectivity Stacks
Wi-Fi 6/6E (hostapd, wpa_supplicant), BLE 5.x (BlueZ), Thread/Matter, LTE/5G (ModemManager, ofono), Ethernet TSN
Development & CI
Yocto autobuilder, Jenkins/GitLab CI pipelines, LAVA for automated hardware testing, Toaster for build management
REFERENCE ARCHITECTURES

Reference Architectures

Custom BSP Stack

Hardware
Bootloader (U-Boot)
Linux Kernel
Root Filesystem (Yocto)
Application Layer

Full custom BSP from silicon to application — optimized boot time, minimal footprint, production-grade security with secure boot chain.

U-Boot SPLLinux 6.x LTS kernelYocto Poky distrosystemdTPM 2.0

OTA Update Architecture

Cloud Update Server
Device Agent
A/B Partition
Rollback Safety
Running System

Resilient over-the-air update system with A/B partitioning, cryptographic verification, and automatic rollback on failure.

SWUpdate agenthawkBit serverdm-verityA/B rootfs partitionsSigned update bundles
CREDENTIALS

Certifications & Ecosystem

Yocto Project ParticipantAGL (Automotive Grade Linux) MemberISO 9001:2015 CertifiedASPICE CL2 Process ComplianceNXP Gold Partner (i.MX platforms)TI Design Network MemberClutch 4.8/5 Rating
FREQUENTLY ASKED

Yocto or Buildroot — which should we use?

Yocto is the right choice for complex products with long lifecycles, multiple variants, and enterprise-grade requirements (OTA, security, compliance). Buildroot is faster to set up and better suited for simpler, resource-constrained devices where build reproducibility is less critical. For automotive, Yocto with AGL is the industry standard. We help clients choose during the architecture phase.

Can you maintain our Linux BSP long-term?

Yes. We offer maintenance contracts covering kernel LTS updates, CVE patching, Yocto release migrations (every 6 months), and security advisory response. Our longest active maintenance engagement is 10+ years for an industrial platform.

How do you handle mixed Linux + RTOS systems?

We use asymmetric multiprocessing (AMP) where the SoC supports it — for example, Linux on Cortex-A cores and FreeRTOS on Cortex-M or Cortex-R cores (NXP i.MX 8M, TI AM64x). For stricter isolation, we deploy Xen or Jailhouse hypervisors to partition the system into safety-critical RTOS domains and general-purpose Linux domains.

What about real-time performance under Linux?

Standard Linux with PREEMPT_RT provides deterministic scheduling down to ~50us worst-case latency, sufficient for most industrial applications. For harder real-time requirements (<10us), we use dedicated RTOS cores via AMP or Xenomai co-kernel. We benchmark latency on target hardware during the evaluation phase.

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