DS4Dongle — Pico 2 W DualShock 4 Bridge

Firmware for the Raspberry Pi Pico 2 W that hosts a DualShock 4 over Bluetooth Classic and presents it to the PC as a wired DualShock 4 v2 (054C:09CC) — including audio to the controller's speaker and headphone jack.

Adapted from awalol/DS5Dongle, which does the same for the DualSense. If you have a DualSense, use DS5Dongle directly.

See Releases for the images.

Status: pre-release. Works on the author's hardware (DS4 v1 + Pico 2 W, Linux host). Microphone input is not implemented yet. Expect rough edges.

Features

• All Buttons work

• Touchpad works (one or two touch points and clicks)

• Gyroscope and Accelerometer works

• LED

• Charging detection

• Wired DS4 v2 USB persona with the real HID report descriptor: gamepad, motion sensors, touchpad, rumble, lightbar

• Calibration passthrough (BT report 0x05 translated to USB report 0x02)

• Audio out to the controller speaker and headphone jack: USB audio at the DS4's native 32 kHz stereo, SBC-encoded on-device (no resampling); routing auto-switches when a headset is plugged into the jack

• Volume/mute from the host mapped to the controller

• Pairing and controller management via the BOOTSEL button, persistent pairings and blacklist in flash

• Configurable over HID feature reports (tools/config_tool.py): polling rate, audio routing, inactivity timeout, wake-on-PS, and more

Flashing

1. Hold BOOTSEL while plugging the Pico 2 W in; it mounts as a USB drive.
2. Copy ds4-bridge.uf2 onto it.

Grab pre-built firmware from the Releases page (ds4-bridge.uf2; the -debug variant adds a USB serial console for troubleshooting and changes the USB persona — don't use it for play).

Pairing

1. With the controller off, hold Share, then PS, until the lightbar double-flashes rapidly.
2. Short-press the Pico's BOOTSEL button. The LED blinks while searching and turns solid when connected; the lightbar flashes gold once.
3. Afterwards a plain PS press reconnects. The dongle only appears on USB while a controller is connected.

BOOTSEL while running: click = pair/switch controller, double-click = reboot, triple-click = reboot into the bootloader for flashing, hold ~1.5 s = forget all controllers.

Building

Requires arm-none-eabi-gcc, CMake, Ninja, and pico-sdk 2.3.0 with TinyUSB pinned to 0.21.0:

git clone --depth 1 --branch 2.3.0 https://github.com/raspberrypi/pico-sdk
git -C pico-sdk submodule update --init --recursive
git -C pico-sdk/lib/tinyusb fetch --depth 1 origin refs/tags/0.21.0:refs/tags/0.21.0
git -C pico-sdk/lib/tinyusb checkout 0.21.0

cmake -S . -B build -G Ninja -DPICO_SDK_PATH=$PWD/pico-sdk
cmake --build build
# → build/ds4-bridge.uf2

-DENABLE_SERIAL=ON -DENABLE_VERBOSE=ON builds the debug variant.

Debugging

The debug firmware (ds4-bridge-debug.uf2, or a -DENABLE_SERIAL=ON build) differs from the production build in three ways: it adds a USB CDC serial console, it stays on the USB bus from boot (the production build hides USB until a controller is connected), and the watchdog is disabled so a fault prints instead of silently rebooting.

To use it:

1. Flash the debug UF2 (see Flashing).

2. Open the serial console — the port appears as soon as the Pico boots:

   # Linux (any of these)
   tio /dev/ttyACM0
   picocom -b 115200 /dev/ttyACM0
   # Windows: PuTTY on the new COM port, 115200 baud

3. Reproduce the problem (pair, connect, play audio). Log lines are prefixed by subsystem: [HCI] Bluetooth link events (inquiry, connect, auth, encryption, disconnect reasons), [L2CAP] HID channel setup and traffic, [BT] button actions and pairing state, [BLACKLIST] pairing blacklist, [AUDIO]/[Audio] USB audio and SBC pipeline, [CMD]/[Config] config reports, [USBHID] report forwarding.

What healthy output looks like: pairing runs Gamepad found → ACL connected → Authentication complete → Encryption change ... enabled=1 → HID Control opened → HID Interrupt opened → Connected DS4 Controller. A Disconnected reason=0x13 right after HID Control opened means the controller aborted the handshake; reason=0x08 is a supervision timeout (range/battery). If the controller connects and immediately drops with the production build but works in debug, suspect the watchdog (a stall >1 s reboots the dongle).

Notes: the debug build's USB persona differs (extra CDC interface, audio visible before a controller connects), so drivers and games may treat it differently — use it for diagnosis only. While USB audio is streaming, the console fills with send-FIFO warnings during (re)connects; pause or suspend the dongle's audio sink to get a clean pairing trace.

Resources

Built on the work of others:

• awalol/DS5Dongle — the codebase this is forked from (BT host, USB bridge, config system, RAM relocation)
• psdevwiki DS4-BT — report layouts, audio report 0x17, CRC scheme
• sensepost dual-pod-shock — DS4 Bluetooth audio research
• GP2040-CE — the DS4 v2 HID report descriptor
• usedbytes/picow_ds4 — prior art for DS4-on-Pico
• Raspberry Pi pico-sdk, BlueKitchen BTstack, TinyUSB

Developed with the assistance of Claude (Fable 5), verified on real hardware.

License

MIT, same as DS5Dongle. See LICENSE.