WebUSB DFU Flasher

Browser-based firmware flashing tool for STM32, AT32 and other DFU-compatible microcontrollers

🚀 Quick Start

Connect

• Put your device in DFU mode: Hold button and power on (or short BOOT0=HIGH on PCB)
• Connect Device: click "Connect to Device" and select DFU device from the dialog

Flash / Verify operation

• Load Firmware: Select or drag & drop a firmware file (.bin, .dfu, .hex, .srec)
• Configure Options:
  • For BIN files: specify flash start address (default: 0x08000000)
  • Enable/disable erase before flashing (leave enabled in most cases)
  • Enable/disable verification after flashing
• Flash: Click "Flash" to start the programming process
• Verify: Click "Verify Only" to check existing firmware without reprogramming

Upload operation

• Open Upload Panel: Click "Upload from Device" button
• Select Range:
  • Choose start sector from dropdown
  • Choose end sector from dropdown
  • Verify calculated size
• Upload: Click "Upload" to read data from device
  • Data read sector-by-sector
  • Progress bar shows completion
  • Data loaded as 'Device Dump' image with format 'bin'
• Save Dump: Click "Save as BIN" to export firmware
  • Choose file name and location
  • File saved with device address and size in name

📱 Supported Devices

• STM32 (VID: 0x0483) — Full DfuSe extension support
• AT32 (VID: 0x2E3C) — Artery microcontrollers
• GD32 (VID: 0x28E9) — GigaDevice
• ESP32-S2/S3 (VID: 0x303A) — Espressif

📁 File Formats

• .bin — Raw binary (requires manual address)
• .dfu — STMicroelectronics DfuSe format with CRC32
• .hex — Intel HEX with extended addressing
• .srec/.s19/.s28/.s37 - Motorola S-Record

⚙️ Core Operations

• Flash (Write)
  • Intelligent sector-based erasure with automatic size detection
  • Progress tracking and multiple memory region support
  • Duplicate sector prevention for overlapping blocks
• Verify (Read & Compare)
  • Post-flash byte-by-byte verification
  • Detailed mismatch reporting with first error location
• Upload from Device (Read Back)
  • Extract firmware for backup or analysis
  • Sector-based range selection from device memory map
  • Save as BIN with custom path

💻 System Requirements

• 🌐 Browser
  • Chrome 86+ (recommended)
  • Edge 86+
  • Opera 72+ (
  • Not supported: Firefox, Safari, Opera on Android
• 🪟 Operating System
  • Windows: WinUSB driver required (install via Zadig)
  • Linux/macOS/Android: No additional drivers needed
• 🛠️ Hardware
  • USB data cable (not charge-only)
  • Device in DFU bootloader mode
  • USB OTG adapter (for Android devices)

🔒 Security & Privacy

• WebUSB requires explicit user permission for each connection
• No persistent storage of device data or firmware
• All operations in browser sandbox
• HTTPS required for production (localhost allowed for development)

⚠️ Important Notes

• Device must be in DFU bootloader mode (not application mode)
  STM32: Set BOOT0=HIGH, then reset/power cycle
• Windows users: Install WinUSB driver via Zadig before first use
  • Download Zadig from zadig.akeo.ie
  • Run Zadig as Administrator
  • Options → List All Devices
  • Select your DFU device (e.g., STM32 or AT32 BOOTLOADER)
  • Choose "WinUSB" from dropdown
  • Click "Install Driver" or "Replace Driver"
  • If you see "Access denied" error — WinUSB driver is not installed