RP2040 Auto Flash — VS Code Extension

Auto-flash your Raspberry Pi Pico / RP2040 UF2 files from VS Code without pressing BOOTSEL — exactly like Arduino IDE does.

How It Works

This extension replicates the 1200bps DTR magic trick used by the Arduino-Pico core (uf2conv.py):

Opens your RP2040's serial COM port at 9600 baud
Asserts DTR (Data Terminal Ready)
Waits ~100ms
Clears DTR
Switches to 1200 baud and closes the port
The RP2040 firmware detects this sequence and reboots into USB bootloader mode
Extension waits for the RPI-RP2 USB drive to appear
Copies your .uf2 file to the drive → RP2040 flashes itself and reboots ✅

⚠️ This trick requires that your RP2040 firmware exposes a USB CDC serial interface. If your firmware has no USB serial, the board must be reset manually the first time (hold BOOTSEL while plugging in), then flash via this extension — from that point on auto-reset works as long as your firmware includes USB serial.

Installation

From VSIX (manual install)

# 1. Clone / download this extension folder
# 2. Install dependencies
npm install

# 3. Package it
npm run package
# → produces rp2040-autoflash-1.0.3.vsix

# 4. Install in VS Code
code --install-extension rp2040-autoflash-1.0.3.vsix

From VS Code

Ctrl+Shift+P → Extensions: Install from VSIX… → select the .vsix file.

Commands

Open the Command Palette (Ctrl+Shift+P) and search for RP2040:

Command	Description
`RP2040: Auto Flash UF2`	Reset board + copy UF2 — full one-click flash
`RP2040: Reset to Bootloader`	Send the 1200bps pulse only (no file copy)
`RP2040: Select Serial Port`	Choose and save the COM port for this workspace
`RP2040: Select UF2 File`	Choose and save the UF2 path for this workspace

Right-click shortcut

Right-click any .uf2 file in the Explorer sidebar → RP2040: Auto Flash UF2

Settings

Open Settings (Ctrl+,) and search for rp2040:

Setting	Default	Description
`rp2040-autoflash.serialPort`	(empty)	COM port (e.g. `COM3`, `/dev/ttyACM0`). Empty = pick each time
`rp2040-autoflash.uf2Path`	(empty)	Path to UF2 file. Empty = pick each time
`rp2040-autoflash.bootloaderWaitMs`	`3000`	Milliseconds to wait for RPI-RP2 drive to appear after reset
`rp2040-autoflash.autoDetectDrive`	`true`	Auto-detect the RPI-RP2 USB drive
`rp2040-autoflash.drivePath`	(empty)	Manual drive path (e.g. `D:\` or `/media/user/RPI-RP2`)

workspace `.vscode/settings.json` example

{
  "rp2040-autoflash.serialPort": "/dev/ttyACM0",
  "rp2040-autoflash.uf2Path": "${workspaceFolder}/build/firmware.uf2",
  "rp2040-autoflash.bootloaderWaitMs": 3000
}

Supported Platforms

Platform	Status
Windows 10/11	✅ Full support
macOS	✅ Full support
Linux (Ubuntu, Debian, Fedora)	✅ Full support

Linux: udev rule (avoid `sudo`)

Add this rule so VS Code can access serial ports without root:

echo 'SUBSYSTEM=="tty", ATTRS{idVendor}=="2e8a", MODE="0666"' | sudo tee /etc/udev/rules.d/99-rp2040.rules
sudo udevadm control --reload-rules && sudo udevadm trigger

Workflow with Pico SDK / CMake

# Build your firmware (CMake)
cd build && cmake .. && make -j4

# The extension will find build/firmware.uf2 automatically if you set uf2Path
# Or right-click firmware.uf2 in VS Code Explorer → RP2040: Auto Flash UF2

Combine with a VS Code Task (`.vscode/tasks.json`)

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Build & Flash RP2040",
      "type": "shell",
      "command": "cd build && make -j4",
      "group": { "kind": "build", "isDefault": true },
      "presentation": { "reveal": "always" },
      "dependsOn": [],
      "postBuild": {
        "command": "rp2040-autoflash.flash"
      }
    }
  ]
}

Troubleshooting

"No serial ports found"

Make sure your RP2040 firmware includes a USB CDC serial interface (stdio_usb_init() in C SDK, or import usb_cdc in CircuitPython).
On Linux, add your user to the dialout group: sudo usermod -aG dialout $USER then log out/in.

"Could not find RPI-RP2 drive"

Increase bootloaderWaitMs to 5000 or more.
On Windows, check Device Manager — the drive should appear as a removable disk.
Set drivePath manually if auto-detect fails.

Reset works but board stays in bootloader

The UF2 file may be corrupt or built for a different board. Verify with picotool info firmware.uf2.

RP2040 Auto Flash

JP-Makers