Open-source alternatives to U Boot

xv6 is a Unix-like educational operating system designed for teaching kernel concepts. It is implemented as an instructional kernel for x86 and RISC-V architectures, featuring a virtual memory manager and support for symmetric multiprocessing. The system is designed to demonstrate core OS principles through a simplified re-implementation of Unix Version 6. It provides a controlled environment for studying system calls, trap handling, and process lifecycles. Its capability surface covers process management, including scheduling and context switching, and memory management via page tables for

This project is an implementation of the Arduino framework for ESP32 microcontrollers, providing a core that enables firmware development using a familiar API. It functions as a microcontroller hardware abstraction layer and a firmware toolchain integration, bridging external development environments to the hardware for compilation and flashing. The system includes an embedded real-time operating system wrapper to manage multi-core execution and task scheduling, alongside a wireless communication suite for TCP/IP networking and Bluetooth Low Energy. It distinguishes itself by providing an obj

This project is a reference library of firmware examples and a development framework for creating embedded C applications on the RP2040 microcontroller. It provides a collection of hardware peripheral drivers and foundational patterns for managing system resources in resource-constrained environments. The library features reference implementations for programmable I/O state machines, allowing for the creation of custom hardware-level protocols. It also provides a multicore embedded framework to distribute computational workloads across multiple processor cores using symmetric processing. The

Open-smartwatch-os is an operating system designed for resource-constrained wearable devices. It provides a development and testing environment that allows developers to build, validate, and debug firmware for smartwatches within a simulated desktop environment before deploying to physical hardware. The project distinguishes itself through a comprehensive suite of tools for hardware emulation and remote diagnostics. By utilizing a hardware abstraction layer and modular driver architecture, it decouples core system logic from specific physical components. This enables developers to run the ope

This repository contains the pre-compiled firmware, bootloader binaries, device tree overlay files, and Linux kernel modules that power Raspberry Pi single-board computers. It provides the foundational system firmware that initializes the hardware and loads an operating system. The boot architecture relies on a proprietary VideoCore GPU that co-processes early initialization, memory partitioning, device tree overlay loading, and mailbox-based peripheral configuration before handing control to the main CPU. This multi-stage boot process uses a chain of small binary stages and loads a raw kerne

This project is an educational resource for developing bare-metal operating systems and kernels from scratch on Raspberry Pi hardware. It provides a structured guide to systems programming using the Rust language, focusing on the implementation of core kernel components that execute directly on ARM-based hardware without the support of an underlying operating system or standard library. The tutorials emphasize a modular architecture that separates hardware-independent kernel logic from processor-specific and board-specific configurations. By utilizing a hardware abstraction layer and distinct

godotenv is a Go library designed to load, parse, and serialize environment configuration files. It provides tools to extract configuration data from files into maps and inject those key-value pairs directly into the system environment of a Go application process. The project includes a configuration file serializer for exporting environment variable maps back into formatted files and a parser for extracting data without modifying the system environment. It supports injecting variables from strings or files into the process environment using priority-based overloading and overwriting. The li

NuttX is a POSIX-compliant real-time operating system designed for microcontrollers ranging from 8-bit to 64-bit architectures. It provides a deterministic execution environment with a real-time task scheduler and a POSIX embedded kernel to ensure portable code execution across diverse hardware targets. The project distinguishes itself through a comprehensive hardware abstraction layer that provides standardized drivers for I2C, SPI, CAN, and USB across various semiconductor chipsets. It also features an embedded networking stack supporting TCP, UDP, IPv4, and IPv6, alongside industrial proto

m1n1 is a low-level bootloader for ARM64-based Apple Silicon hardware. It serves as a firmware tool and experimentation environment for loading external kernels and non-native operating systems. The project enables the execution of concatenated binary payloads containing kernels, device trees, and ramdisks. It provides a platform for firmware experimentation and the deployment of custom kernels on Apple Silicon chips. The system covers low-level hardware abstraction, including memory-mapped register access, device tree transmission, and stage-based bootloading. It also includes UART-based se

This project is a cross-platform emulator designed to execute software originally developed for the PlayStation 2 console on modern computing hardware. By replicating the original processor and graphics architecture, it allows users to run legacy game discs and digital backups within a virtual environment on contemporary desktop and laptop systems. The software distinguishes itself through advanced graphics enhancement engineering, which enables users to adjust rendering resolutions, apply texture filtering, and utilize community-created patches to improve visual fidelity beyond original hard

python-dotenv is a library and command line interface for managing environment variables in Python applications. It functions as a configuration parser and loader that reads key-value pairs from files and injects them into the system environment, enabling the decoupling of application configuration from source code. The project provides a command line interface for manipulating and editing environment variables within configuration files. It also includes a mechanism for recursive variable interpolation, allowing dynamic placeholders within configuration files to be resolved using existing en

This library is a PHP environment variable loader and configuration parser. It extracts key-value pairs from local text files to populate global server and system environment arrays, ensuring that sensitive credentials and application settings remain separate from the source code. The tool implements twelve-factor app configuration principles by mapping local files to process-level variables. It utilizes a regex-based parser to identify variable assignments while stripping comments and whitespace, and it includes guards to prevent local configuration files from overwriting existing host-level

Lua RTOS for ESP32 is a real-time operating system designed for ESP32 microcontrollers that integrates a lightweight Lua interpreter to manage hardware resources and application logic. It utilizes a micro-kernel architecture to provide preemptive task scheduling, ensuring deterministic timing and reliable concurrency for embedded operations on resource-constrained hardware. The system distinguishes itself by providing a unified hardware abstraction layer that maps high-level programming commands directly to peripheral registers. This allows developers to interact with sensors, actuators, and

Implementation of a bulletproof node.js API 🛡️

This project is an educational framework and toolkit designed for developing and testing operating system kernels. It provides a structured environment for implementing fundamental system primitives, including virtual memory management, preemptive process scheduling, and filesystem organization, using Rust and C. The framework is specifically oriented toward RISC-V and x86 architectures, serving as a laboratory for learning how to build core system software from the ground up. The project distinguishes itself by supporting both bare-metal deployment and hardware emulation, allowing developers

MAME is a vintage hardware emulation platform designed to recreate the circuitry of arcade games, computers, and consoles to run original software on modern devices. It functions as a retro gaming preservation framework for managing, verifying, and archiving ROM sets and disk images to ensure long-term software accessibility. The project features a system debugging tool for inspecting emulated memory, CPU registers, and execution flow via breakpoints and disassembly. It also includes a Lua-based automation layer that exposes core system state and hardware controls for custom behavior and anal

This project is a tutorial for developing a custom bare metal operating system specifically for the Raspberry Pi 4. It provides the guidance and resources necessary to write software that interacts directly with hardware without the use of a pre-existing kernel. The project centers on an ARM64 cross-compilation toolchain and a build pipeline that transforms source code into raw binary images. It utilizes linker scripts to define physical memory addresses and section placements, ensuring the resulting binary loads at the correct hardware entry point. The codebase covers direct hardware interf

This project is a comprehensive guide to architectural standards and coding patterns for developing maintainable applications within the Laravel framework. It focuses on clean code standards, applying the single responsibility and DRY principles to ensure codebase predictability and consistency. The guide emphasizes decoupling components by moving business logic into service layers and shifting input validation into dedicated request classes to keep controllers lean. It advocates for the use of a service container and dependency injection to reduce class coupling and improve testability. The

Contiki is an operating system designed for resource-constrained embedded devices and the Internet of Things. It provides a lightweight, event-driven kernel that enables multitasking and low-power wireless network connectivity on hardware with extremely limited memory and processing power. The system distinguishes itself through a stackless threading model that allows for a blocking-style programming interface while maintaining a minimal memory footprint. It supports dynamic module and firmware management, enabling the loading and linking of relocatable binary code at runtime to update applic

MicroPython is a lean implementation of Python 3 optimized to run on microcontrollers and other resource-constrained systems. It serves as a cross-platform embedded runtime and hardware abstraction layer, providing a firmware framework that maps high-level software commands to specific microcontroller registers across diverse processor architectures. The project functions as an embedded language interpreter that enables rapid prototyping on hardware through an interactive read-eval-print loop. It supports a wide range of target environments, including ARM, ESP32, STM32, RISC-V, and WebAssembl

rpi4-osdev is a project for bare metal operating system development targeting the Raspberry Pi 4. It focuses on creating a custom operating system that runs directly on the hardware without an underlying kernel or abstraction layer. The project provides a codebase and instructional guide for developing a low-level system from scratch. This process involves transitioning from early boot code to kernel execution on the ARM64 architecture. The technical scope covers embedded system bootstrapping and low-level hardware interfacing. This includes managing memory-mapped I/O, physical address mappi

OpenCorePkg is a modular UEFI bootloader designed to initialize hardware and facilitate the loading of modern operating systems on non-standard or unsupported hardware. It functions as a comprehensive firmware emulation environment, providing the necessary runtime services and memory management to bridge the gap between diverse hardware configurations and operating system requirements. The project distinguishes itself through its ability to perform runtime kernel patching and system firmware modification, allowing for the injection of drivers and the manipulation of hardware tables during the

miniaudio is a single-file C audio library used for audio playback, capture, and hardware interfacing across multiple operating systems. It functions as an audio hardware abstraction layer, an audio processing engine, an audio synthesis engine, and a codec and resampler. The project implements a node-graph based system for routing digital audio signals, mixing, and 3D spatialization. It also includes a programmatic generator for noise patterns and basic waveforms used for sound creation and signal testing. The library covers digital signal processing, including audio format conversion and sa

This project is an OpenWrt firmware builder and specialized Linux router distribution designed to repurpose Amlogic S9xxx series hardware into functional routers. It provides a hardware adaptation layer consisting of kernel modifications and drivers that enable the operating system to run on Amlogic ARM SoC devices. The project features an automated firmware pipeline for scheduling, building, and distributing custom images. It includes a device recovery toolkit for bootstrapping, flashing, and restoring factory images, and supports the conversion of devices previously running different mobile

This project is a comprehensive research platform designed for the end-to-end lifecycle of robotic learning. It provides a modular framework for training neural network policies—specifically through imitation and reinforcement learning—and deploying them onto physical robotic hardware. By offering a unified interface for hardware abstraction, the platform decouples high-level control logic from the specific sensors and actuators of diverse robotic systems. The framework distinguishes itself through a standardized approach to data and policy management. It utilizes a consistent schema for reco

This project is a high-performance, lightweight C graphics library designed for creating interactive user interfaces on resource-constrained embedded hardware. It functions as a comprehensive framework that provides a widget toolkit, a rendering engine, and hardware-agnostic drivers to support the development of graphical displays on microcontrollers and embedded systems. The framework distinguishes itself through a flexible, object-oriented widget hierarchy and a declarative layout engine that supports responsive design patterns like flexbox and grid systems. It enables developers to synchro

SDL is a cross-platform development library that provides low-level access to audio, keyboard, mouse, joystick, and graphics hardware. It functions as a hardware abstraction layer, mapping diverse operating system interfaces into a unified set of functions to ensure consistent performance across different computing environments. The library serves as a foundation for multimedia and interactive application development by providing an integrated audio processing engine and a graphics rendering framework. It manages the complexities of hardware communication by normalizing raw input events and p