`OpenPEQ` (Hardware DSP Flasher & Web Equalizer Suite)

⚡ Live Web Flasher in action: Drag real-time biquad curve handles, audition in volatile RAM, or save to persistent hardware NVRAM in <50ms.

An open-source hardware DSP flashing suite, WebHID browser flasher, and host equalizer bridge for portable USB-C DAC dongles, DSP upgrade cables, and In-Ear Monitors (IEMs).

Save custom Parametric EQ profiles (including AutoEq targets from squig.link) directly into onboard non-volatile hardware memory (NVRAM). Settings persist natively across iPhones, Android, Macs, Windows, Linux PCs, iPads, and gaming consoles without running any background apps.

⚡ Try the Web Flasher (Zero Install)

Run the full hardware flasher directly in your browser via WebHID (Chrome, Brave, Edge):

👉 Launch Web Flasher (GitHub Pages)

100% Client-Side & Private (no audio or device data leaves your browser).
Real-time Interactive SVG Biquad Curve with draggable band handles.
AutoEq Database Integration (search over 5,000+ headphone & IEM measurements).
2-Way Hardware Readback & Live Audition in RAM before saving to persistent NVRAM.
Built-in Safety Guardrails: NVRAM Flash Wear-Out Tracker & Conexant fixed mask ROM protection.

Tip

Linux Users: Linux restricts /dev/hidraw* devices to root by default. See Linux WebHID & udev Setup below to enable browser access in 10 seconds.

📸 Architecture & Feature Slides

Click to preview presentation & feature slides (5-Slide Infographic Deck)

Slide 1: Overview & Value Proposition	Slide 2: The Status Quo vs Open Source

Slide 3: Web Flasher UI & Biquad Curve	Slide 4: Multi-Tier Hardware Protections

Slide 5: Hardware Compatibility & Universal Portability

📋 Hardware Compatibility Matrix

See COMPATIBILITY.md for our full breakdown of all 35+ cataloged DACs across 4 status tiers:

Status	Category	Highlighted Devices
🟢	Hardware Verified & Tested	CrinEar Protocol Micro & Max, Tanchjim SPACE Pro, Kiwi Ears Allegro Mini, Moondrop FreeDSP / May Cable, TANGZU Wan'er S.G II Cable, BASN BmasterX 6 Plug, TTGK CX31993, Rythflo WD01, Bluetrum AB13X
🟡	Protocol Implemented (Awaiting Silicon Tester)	TRUTHEAR KEYX, Moondrop Chu II DSP, Tanchjim ONE DSP, FiiO / JadeAudio JA11, Fosi Audio DS3, FiiO LS-TC2, Celest Wyvern Abyss, Simgot EW300 DSP
🔵	Protocol In Development (Help Wanted)	FiiO KA15, FiiO KA17, FiiO BTR13, ddHiFi Memory DSP
🔴	Fixed Mask ROM (Host DSP & Qudelix Interop)	Qudelix-5K Profile Sync, Conexant CX31993 (TTGK, JCALLY JM6 Pro), Apple USB-C A2049, Moondrop Dawn Pro

🛡️ Silicon Safety & Volume Lockout Prevention

dac-peq-manager was built from reverse engineering physical hardware captures to eliminate common firmware bricking and volume lockout bugs:

Hardware Volume Lockout Prevention:
- On KTMicro KT02H20 hardware (Kiwi Ears Allegro Mini), writing register 0x11 (DAC reconstruction filter from JA11) or 0x66 (preamp) overwrites internal MCU codec attenuation registers, locking out physical volume buttons on iOS/Android.
- dac-peq-manager strictly restricts writes to the 5 PEQ bands (0x26–0x2F) and Slot 3 (0x24), guaranteeing full native volume slider response on iPhone and YouTube Music.
Official Factory Reset (0x43 CLEAR):
- If volume controls are locked by other tools, zeroing bands will not restore them. The official vendor 0x43 CLEAR command completely wipes corrupted NVRAM and soft-reboots the MCU. Available via CLI (dac-peq-manager reset -y) and the Web Flasher.
Conexant CX31993 OTP Safety Lock:
- Conexant CX31993 devices use fixed mask ROM with One-Time Programmable (OTP) registers. Sending KTMicro HID register writes risks corrupting descriptors. Flashing is automatically blocked for Conexant hardware and safely routed to host-side DSP exporters.
2X Clock Divisor Auto-Detection:
- Automatically detects whether firmware has the 2X biquad clock divisor bug (bcdDevice <= 0x0100), halving calculation frequencies (f / 2) where needed and running native clocks on modern firmwares.
Physical NVRAM Wear-Out Health Tracker:
- EEPROMs lack wear leveling (~10k–100k cycles). The built-in counter tracks total flash commits per VID:PID and alerts users if writes exceed safe daily thresholds.

💻 CLI Quickstart (Python)

1. Installation

git clone https://github.com/JohnnyGuerra/openpeq.git
cd openpeq
pip install -e dac-peq-manager/

2. Basic Commands

# Scan and inspect connected USB DACs
openpeq scan

# Audition a preset in live RAM (instant, zero flash wear)
openpeq apply bmasterx6

# Permanently save preset into hardware NVRAM
openpeq flash bmasterx6

# Read active PEQ bands directly from DAC hardware
openpeq read

# Factory reset NVRAM and recover volume control
openpeq reset -y

# Check flash memory write endurance history
openpeq flash-history

# Export 10-band target profile for software equalizers
openpeq export-pipewire bmasterx6 --full-target
openpeq export-apo bmasterx6 --full-target

🌐 OS Compatibility & Browser Requirements

The Web Flasher runs client-side in desktop Chromium browsers (Google Chrome, Brave, Microsoft Edge, Opera) using the official W3C WebHID API:

Operating System	Setup Required	Admin / Driver Needed?	Notes
macOS (Apple Silicon & Intel)	Zero (Plug & Play)	❌ No	Handled automatically via `IOKit`. Plug in and click Connect.
Windows (10 & 11)	Zero (Plug & Play)	❌ No	Works out of the box. Note: Close any OEM companion software (e.g. Tanchjim PC app) if running, as Windows grants background apps exclusive HID locks.
ChromeOS (Chromebooks)	Zero (Plug & Play)	❌ No	Works natively in the ChromeOS browser.
Linux (Arch, Ubuntu, Fedora, Debian)	One-time udev rule	❌ No (after rule)	Linux restricts `/dev/hidraw*` to root by default. Run our one-line udev setup to grant desktop seat access (`uaccess`).
iOS / iPadOS / Android	Save once from PC	N/A	Apple WebKit does not expose WebHID to mobile browsers. Save your EQ curve once from a PC/Mac/Chromebook, and it remains permanently active in the DAC hardware on your phone.

🐧 Linux WebHID & udev Setup

On Linux distributions (Arch, Ubuntu, Debian, Fedora), access to raw USB HID nodes (/dev/hidraw*) is restricted to root by default. If you encounter a NotAllowedError: Failed to open the device in Chrome/Edge, configure non-root user access via our udev rules:

Quick One-Liner Install

sudo cp udev/99-dac-peq.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules && sudo udevadm trigger

Or write the rule directly:

sudo tee /etc/udev/rules.d/99-dac-peq.rules << 'EOF'
SUBSYSTEM=="usb", ATTRS{idVendor}=="31b2", TAG+="uaccess"
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="31b2", MODE="0666", TAG+="uaccess"
SUBSYSTEM=="usb", ATTRS{idVendor}=="3302", TAG+="uaccess"
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="3302", MODE="0666", TAG+="uaccess"
SUBSYSTEM=="usb", ATTRS{idVendor}=="2972", TAG+="uaccess"
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="2972", MODE="0666", TAG+="uaccess"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="0023", TAG+="uaccess"
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="0023", MODE="0666", TAG+="uaccess"
SUBSYSTEM=="usb", ATTRS{idVendor}=="262a", TAG+="uaccess"
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="262a", MODE="0666", TAG+="uaccess"
EOF
sudo udevadm control --reload-rules && sudo udevadm trigger

Note

Ubuntu / Debian Snap Warning: If you run Chromium or Chrome installed via Ubuntu Snap, Snap's AppArmor sandbox blocks access to /dev/hidraw* even with udev rules. Use the official .deb package or a Flatpak with device access permissions enabled.

🤝 Community & Contributing

We need your help testing devices and capturing USB packets!

Read our CONTRIBUTING.md guide to see how to capture WebHID sendReport logs in Chrome DevTools or Wireshark.
Own a device marked 🟡? Submit a Hardware Verification Report!
Want support for a new DAC? Open a New DAC Support Request.

📜 License & Disclaimers

License: MIT License
Disclaimer: OpenPEQ is an independent, community-driven open-source project. Not affiliated with KTMicro, Kiwi Ears, FiiO, Moondrop, Tanchjim, or Truthear.

✒️ Citation & Attribution

If you use OpenPEQ, its reverse-engineered KTMicro/WalkPlay USB register maps, or the dac-peq-core Rust engine in your own project, fork, or research, please provide attribution:

Guerra, J. (2026). OpenPEQ: Universal hardware DSP flasher & Web equalizer for portable USB-C DACs and IEMs.
GitHub: https://github.com/JohnnyGuerra/openpeq

@software{guerra2026openpeq,
  author = {Johnny Guerra},
  title = {OpenPEQ: Universal hardware DSP flasher & Web equalizer for portable USB-C DACs and IEMs},
  url = {https://github.com/JohnnyGuerra/openpeq},
  year = {2026}
}

Name		Name	Last commit message	Last commit date
.github		.github
dac-peq-manager		dac-peq-manager
media		media
metrics		metrics
scripts		scripts
udev		udev
.gitignore		.gitignore
CITATION.cff		CITATION.cff
COMPATIBILITY.md		COMPATIBILITY.md
CONTRIBUTING.md		CONTRIBUTING.md
GEMINI.md		GEMINI.md
LICENSE		LICENSE
README.md		README.md
SECURITY.md		SECURITY.md

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`OpenPEQ` (Hardware DSP Flasher & Web Equalizer Suite)

⚡ Try the Web Flasher (Zero Install)

📸 Architecture & Feature Slides

📋 Hardware Compatibility Matrix

🛡️ Silicon Safety & Volume Lockout Prevention

💻 CLI Quickstart (Python)

1. Installation

2. Basic Commands

🌐 OS Compatibility & Browser Requirements

🐧 Linux WebHID & udev Setup

Quick One-Liner Install

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OpenPEQ (Hardware DSP Flasher & Web Equalizer Suite)

⚡ Try the Web Flasher (Zero Install)

📸 Architecture & Feature Slides

📋 Hardware Compatibility Matrix

🛡️ Silicon Safety & Volume Lockout Prevention

💻 CLI Quickstart (Python)

1. Installation

2. Basic Commands

🌐 OS Compatibility & Browser Requirements

🐧 Linux WebHID & udev Setup

Quick One-Liner Install

🤝 Community & Contributing

📜 License & Disclaimers

✒️ Citation & Attribution

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`OpenPEQ` (Hardware DSP Flasher & Web Equalizer Suite)