Open-source alternatives to Limine

LiteX is an FPGA SoC development suite and SoC builder framework used to programmatically design system-on-chips. It provides a hardware description toolchain that uses a scriptable framework to define hardware layouts and automate the generation of hardware description language code. The project distinguishes itself by orchestrating multiple vendor and open-source toolchains to synthesize digital logic and generate deployable bitstreams. It supports multi-language logic integration, allowing disparate hardware description languages to be combined into a single project. The framework covers

GEF is a Python-based extension for GDB that serves as a framework for binary analysis, exploit development, and low-level debugging. It functions as a dynamic analysis extension designed to assist in reverse engineering workflows and malware analysis by enhancing the debugger's ability to inspect process state and memory. The project is distinguished by its specialized heap analysis tools, which allow for the inspection of glibc heap arenas, bins, and chunks to detect memory corruption. It also provides a dedicated toolkit for exploit development, including cyclic pattern generation for offs

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

This repository contains the complete source code for the OpenBSD operating system and its base utilities. It is a Unix-like operating system focused on a secure, portable, and multi-user environment, featuring a C-based system kernel that manages hardware resources and provides essential services. The project provides a source-based system construction model to compile the core kernel and base utilities from raw files. It includes a cross-compilation toolchain for generating the tools and headers necessary to build binaries for target architectures different from the host machine. The codeb

Hekate is a bootloader and system recovery tool for Nintendo Switch hardware. It functions as a multi-OS boot manager that allows the execution of binary payloads and the launching of stock firmware, custom firmware, Android, and Linux through a graphical interface. The project provides a suite of recovery and system modification tools, including the ability to create and restore full backups of internal storage. It also features a USB HID gamepad emulator that maps device controller inputs to USB signals for interacting with external computers. The software covers broad capability areas inc

XNU is an operating system kernel designed to manage system hardware and process execution across different processor architectures. It utilizes a hybrid microkernel design that combines microkernel message passing with monolithic kernel performance by embedding critical subsystems into a single address space. The project implements a port-based asynchronous messaging system for communication between kernel tasks and userspace processes. It manages hardware interactions through a layered driver architecture and enforces system-wide security policies via a mandatory access control interface.

rCore is a Rust-based operating system kernel and microkernel designed for Linux compatibility. It functions as a self-hosted development kit that implements a system call interface to support the execution of standard Linux userspace applications. The system is designed for modularity, featuring a mechanism for loading and integrating kernel modules into the active environment without requiring a system reboot. The kernel provides core operating system capabilities, including virtual memory mapping for process isolation, a disk-based file system for data persistence, and a layered network p

ReactOS is an open-source operating system designed to be binary compatible with Windows applications and drivers. It consists of a low-level system kernel that manages hardware resources and a binary compatibility layer that enables the execution of software designed for the Windows binary interface. The project implements a cross-platform build system and toolchain for compiling and deploying bootable operating system images across different hardware architectures. This includes the use of cross-compilation toolchains and a hardware-abstraction layer to support various processor and motherb

This operating system microkernel is written in Rust, focusing on safety, modularity, and POSIX compatibility for modern hardware. It implements a microkernel architecture that separates hardware drivers and system services into isolated userspace processes for fault tolerance, while providing standard Unix-like system calls and process primitives on a memory-safe codebase. The system handles low-level hardware abstraction through a virtual memory management layer that maps virtual addresses to physical pages uniformly across disparate architectures, alongside hardware memory management opera

This project is a Linux kernel designed for Windows Linux integration, providing the underlying operating system kernel required to execute binary files and applications within the Windows Subsystem for Linux. It utilizes hypervisor-based virtualization to run a full kernel within a lightweight utility virtual machine managed by a Windows host. The repository enables the customization and compilation of the kernel from source. This allows for the modification of system behavior, the addition of specific drivers, and the tailoring of hardware compatibility for virtualized environments. The sy

This project is a collection of minimal operating systems, bootloaders, and hardware drivers used to demonstrate low-level x86 system programming and hardware interfacing. It serves as a kernel development toolkit and a system programming lab designed for testing architecture concepts and hardware behavior within a system emulator. The repository provides reference implementations for creating bootable disk images and loading kernel stages. It includes guides for implementing protected mode transitions, memory paging, interrupt descriptor tables, and symmetric multiprocessing on x86 hardware.

This repository provides the Android device kernel and the corresponding Linux kernel source tree. It serves as the foundational codebase for managing the hardware architecture and power management of mobile devices. The project includes a comprehensive mobile hardware driver set designed to manage device-specific components, such as CPUs, GPUs, and cellular modems. The source code supports activities including Android kernel customization, custom ROM development, Linux kernel auditing, and mobile driver development.

TinyGo is a specialized compiler and development toolkit designed to bring the Go programming language to resource-constrained microcontrollers and WebAssembly environments. It provides a bare-metal runtime environment that enables high-level code execution without the need for a traditional operating system, utilizing an LLVM-based backend to generate efficient machine instructions. The project distinguishes itself through aggressive optimization techniques tailored for small hardware, including a static memory allocation strategy and whole-program dead code elimination that significantly re

Velociraptor is a digital forensics and incident response platform, endpoint detection and response system, and visibility tool. It provides a query engine and remote forensic collector used to hunt for indicators of compromise and perform triage across a fleet of hosts. The system is distinguished by its specialized query language for interrogating host state and parsing binary files. It features a notebook environment that combines markdown documentation with executable query cells to standardize investigative workflows and enable collaborative reporting. The platform covers a wide range o

This project is a comprehensive technical manual for installing macOS on non-Apple x86 hardware using the OpenCore bootloader. It serves as a configuration guide for emulating Apple hardware and patching system firmware to achieve operating system compatibility on PCs. The documentation provides detailed instructions for SMBIOS hardware emulation, including the generation of system identifiers and model profiles. It covers the application of ACPI table patches to enable native power management and the modification of UEFI runtime services to resolve memory map and write protection issues. Th

Mezzano is a self-hosted operating system written entirely in Common Lisp. It employs a language-integrated kernel architecture where both the kernel and user-space applications execute within a single, unified high-level language runtime. The system is designed for both bare-metal environments, booting from physical external media, and as a guest operating system within virtual machine software. It implements symmetric multiprocessing to distribute computational workloads across multiple CPU cores. The environment includes capabilities for automated memory recovery via generational garbage

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

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

smoltcp is a standalone TCP/IP network stack written in Rust, designed specifically for bare-metal and embedded systems. It provides a memory-safe implementation of the internet protocol suite that operates without requiring dynamic heap allocation. The project is distinguished by its heap-less memory management, using fixed-size buffers and manually allocated memory to ensure deterministic performance. It employs zero-copy packet processing and an interface-based hardware abstraction to decouple the network stack from physical hardware. The stack covers a broad range of networking capabilit

Disko is a declarative configuration system for managing Linux disk partitioning, filesystem formatting, and LUKS encryption setup. It functions as a disk provisioner that allows users to define disk layouts and mount points through configuration files rather than manual commands. The project focuses on providing reproducible system installations by defining storage provisioning as code. It specifically automates the creation of partition tables, the setup of encrypted storage containers, and the configuration of filesystem layouts for NixOS systems. The toolset includes a command-line inter

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

Arpl is a bootloader manager and custom kernel loader for network attached storage devices. It provides a network boot environment to automate the fetching, flashing, and installation of modified operating systems and kernels onto hardware storage. The project distinguishes itself through a remote management suite that exposes bootloader controls via a web browser, secure shell connection, or local terminal. It utilizes RSS feeds to automate the retrieval of the latest system images and version metadata for online updates. The system handles hardware boot configuration by mapping network int

Atmosphere is a custom firmware for the Nintendo Switch that provides core system components for loading custom kernels, managing modified operating systems, and redirecting hardware storage. It functions as a customized operating system designed to enable deep system modification and functional extensions. The project distinguishes itself through a system module injector and an application patching engine that allow for the loading of custom binary modules and patches to add features to the console. It also includes a virtual storage manager that redirects internal hardware writes to a virtu

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

OSV is a unikernel operating system and cloud-native execution environment designed to run as a secure microVM on hypervisors such as KVM, Firecracker, Xen, and VMware. It functions as a Linux binary compatible runtime, allowing unmodified Linux binaries to be executed as secure microVMs without requiring recompilation. The project distinguishes itself through its ability to package applications into minimal bootable images and its provide of a virtual machine management API. This REST interface enables remote monitoring of system health, management of execution traces, and control over guest

This project is a cross-compiler toolchain for RISC-V software development. It provides the necessary components to compile C and C++ source code into executable binaries and libraries specifically for the RISC-V hardware architecture. The toolchain supports multi-architecture binary generation and multilib capabilities, allowing a single installation to target various instruction set specifications and bit-widths. It integrates with alternative compilers such as LLVM and Clang and includes a bootstrapped build pipeline to produce high-performance versions of the tools. The system covers bro

This project is a C-based heap management library designed for systems programming environments that require manual control over memory lifecycles. It provides the fundamental utilities necessary to initialize a designated region of memory and perform dynamic allocation and deallocation of memory blocks. The library utilizes a linked-list-based tracking system to manage memory segments, employing a first-fit strategy to locate available space within the heap. To maintain memory organization and minimize fragmentation, it implements boundary-tag coalescing, which automatically merges adjacent