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⚡ What is JustFlash?​

JustFlash is a browser-based tool that instantly flashes firmware to your microcontroller boards — no IDE, no cables, no setup required.

  • 💻 Runs entirely in your browser
  • 📥 Uses precompiled .bin or .hex files
  • 🔌 Supports USB-connected boards like ESP32, ESP8266, and Arduino Uno (experimental)

✅ Supported Boards​

  • ESP32 DevKit v1
  • ESP32-S2 / ESP32-S3 (native USB only)
  • ESP8266 NodeMCU
  • Wemos D1 Mini
  • Arduino Uno (experimental via WebSerial)
Boot Mode Reminder

Some boards like ESP8266/ESP32 may require entering bootloader mode by holding FLASH and pressing RESET during connection.

🌐 Supported Browsers​

BrowserPlatformWebUSB Support
ChromeDesktop✅ Yes
EdgeDesktop✅ Yes
Chrome Android⚠️ Partial❌ Not Reliable
Safari iOS❌ No❌ No
Firefox❌ No❌ No
Mobile Not Supported

⚠️ JustFlash does not work on mobile devices.
Please use a desktop browser like Chrome or Edge with WebUSB support to flash your board.

🚀 How to Use JustFlash​

📸 Step-by-step Instructions:​

  1. Connect your supported board (ESP32/ESP8266/Arduino) via USB.
  2. Click the Just Flash button below.
  3. Select the COM port when prompted.
  4. Wait while the firmware is written.
  5. Your board will reboot and start running the program.

🎬 Visual Steps​

🔥 Flash Your Board​

🔷 ESP32 LED Blink Firmware​

🔌 Loading flasher...

🔌 Make sure your ESP32 board is connected via USB.
A popup will ask for permission to access it.

What happens when you click "Just Flash"?
  • A WebUSB/WebSerial dialog opens to select the device.
  • The firmware flashes directly to your board.
  • No drivers or software required.
Can't flash from browser?

If the WebUSB popup doesn’t appear, download the firmware and flash it using offline tools like:

📥 Download ESP firmware.bin
📥 Download Arduino firmware.hex