{
  "added_at": "2026-11-08",
  "additional_evidence_urls": [
    "https://github.com/BenevolentFutures/fosi-md3/blob/c34b4bf757013764abf8e45c3c9d61c53a397042/docs/hardware.md"
  ],
  "category": "reconstruction-cases",
  "class": "hardware",
  "description_en": "fosi-md3 investigates the Fosi Audio MD3 USB DAC and implements replacement firmware for its ESP32-S3 controller. Its notes map the USB mux, DAC I2C control, Savitech link and stock settings record from hardware observation and firmware disassembly; the ESP-IDF implementation preserves audio control and photo storage. The author reports testing on one unit.",
  "description_zh": "fosi-md3 研究 Fosi Audio MD3 USB DAC，并为其 ESP32-S3 控制器实现替代固件。笔记依据硬件观察与原厂固件反汇编，记录 USB 切换、DAC 的 I2C 控制、Savitech 链路及设置记录；ESP-IDF 实现保留音频控制与照片存储。作者报告仅在一台设备上测试。",
  "entry_url": "https://awesomerea.org/resources/fosi-md3-case/",
  "entry_url_zh": "https://awesomerea.org/zh/resources/fosi-md3-case/",
  "evidence_class": 2,
  "evidence_status": "observed",
  "evidence_url": "https://github.com/BenevolentFutures/fosi-md3/blob/c34b4bf757013764abf8e45c3c9d61c53a397042/README.md",
  "group": "cases",
  "id": "fosi-md3-case",
  "json_url": "https://awesomerea.org/resources/fosi-md3-case/record.json",
  "kind": "case-study",
  "markdown_url": "https://awesomerea.org/resources/fosi-md3-case/index.md",
  "markdown_url_zh": "https://awesomerea.org/zh/resources/fosi-md3-case/index.md",
  "name": "Fosi Audio MD3: mapping the DAC and replacing its controller firmware",
  "name_zh": "Fosi Audio MD3：分析 DAC 并替换控制器固件",
  "record_type": "resource",
  "relationship": "independent-reconstruction",
  "requirement_facets": [
    "prerequisites",
    "prerequisites",
    "limits",
    "license"
  ],
  "requirements": [
    "A Fosi Audio MD3 unit and a backup of its own 32 MB flash for restoration.",
    "ESP-IDF 5.5.1 and LVGL 9.2 for the replacement firmware; documented use was on macOS.",
    "The author reports testing on one unit; power transitions remain unverified.",
    "MIT license for the repository's original code and documentation."
  ],
  "requirements_zh": [
    "需要 Fosi Audio MD3 设备，并先备份该设备的 32 MB 闪存以便恢复。",
    "替代固件需要 ESP-IDF 5.5.1 和 LVGL 9.2；文档中的操作平台为 macOS。",
    "作者报告仅在一台设备上测试；电源状态切换尚未验证。",
    "仓库原创代码和文档采用 MIT 许可证。"
  ],
  "scope": "unknown",
  "targets": [
    "firmware",
    "protocol"
  ],
  "url": "https://github.com/BenevolentFutures/fosi-md3",
  "verification": "source-reviewed",
  "verified_at": "2026-11-06"
}