Flash firmware to your eSpa device directly from your browser

Already wired in? Update over Wi-Fi instead

No USB cable, no need to pull the eSpa out of your spa — just open the update page on your home network.

espa.local/fota

Select Your Device

Available Releases

Loading releases...

Flash Custom Binary

Upload and flash locally-built firmware binaries directly from your computer.

Factory Binary

Application Binary

File-system Binary

Use a factory image by itself, or select an application and optionally a file-system image. Application and file-system offsets default from the configured partition layout and may be changed.

Building from Source

Pre-built firmware binaries are available in the releases above. If you need to build custom firmware, you can compile from source using PlatformIO:

PlatformIO Build for esp32dev

Change the device target above to update these instructions

1. Clone and build firmware:

git clone
cd
pio run -e esp32dev

2. Build SPIFFS filesystem:

pio run -e esp32dev -t buildfs

3. Flash using PlatformIO:

pio run -e esp32dev -t upload
pio run -e esp32dev -t uploadfs

Alternative: Flash using this website:

Use a merged factory image at 0x0, or upload firmware.bin as an application image and optionally spiffs.bin as a file-system image. The custom tab supplies partition defaults and allows application and file-system offsets to be changed.

Release Details

How to Flash Firmware

Already Installed? Flash Wirelessly

If your eSpa is already wired into your spa and connected to your home Wi-Fi, you can update it over the air — no USB cable and no need to remove the device. Visit http://espa.local/fota from any device on the same network and upload the firmware there.

Note: USB flashing (below) is only required for the first-time install, or if the eSpa can't join your Wi-Fi network.

Quick Start Guide

  1. 1
    Select Your Device

    Choose your device target from the dropdown menu. The chip family will be set automatically based on the hardware specification.

  2. 2
    Connect via USB

    Connect your ESP device to your computer using a USB cable. Make sure the cable supports data transfer (not just charging).

  3. 3
    Choose Firmware

    Browse the available releases and click "Flash" on the version you want to install.

  4. 4
    Select Serial Port

    Click "Connect" and select your device's serial port from the browser dialog. It usually appears as "USB Serial" or similar.

  5. 5
    Wait for Completion

    The flashing process will take 1-2 minutes. Don't disconnect your device until it's complete.

Browser Support

This tool requires WebSerial API support. Compatible browsers include:

  • Google Chrome (Desktop)
  • Microsoft Edge (Desktop)
  • Opera (Desktop)

Note: Mobile browsers and Firefox do not currently support WebSerial.

Troubleshooting

Device not detected?

Try a different USB cable or port. Some cables are charge-only and don't support data transfer.

Flashing failed?

Make sure you selected the correct device target. Press and hold the BOOT button on your device, then try again.

Need more help?

Visit espa.diy for documentation and community support.