Based on arduino-littlefs-uploader by (C) 2023 Earle F. Philhower, III
MIT licensed, see LICENSE.md
SPIFFS uploader compatible with Arduino IDE 2.2.1 or higher. For use with the Raspberry Pi Pico RP2040 Arduino core arduino-pico, the community ESP8266 Arduino core and the community ESP32 Arduino core.
[Ctrl] + [Shift] + [P], then "Upload SPIFFS to Pico/ESP8266/ESP32".
On macOS, press [⌘] + [Shift] + [P] to open the Command Palette in the Arduino IDE, then "Upload SPIFFS to Pico/ESP8266/ESP32".
The first sketch auto-opened by the IDE presently may have corrupted state which causes uploads to fail. To work around this, you can change the board once (to anything) and then change it back to your proper board. You can also open another sketch, close the auto-opened one, then re-open it.
A fix is already in the Arduino repository for this issue.
If you get:
A fatal error occurred: Could not open <serial port>, the port doesn't exist
ERROR: Upload failed, error code: 2
Make sure that you close any open Serial Monitor windows.
Copy the VSIX file to ~/.arduinoIDE/plugins/ on Mac and Linux or C:\Users\<username>\.arduinoIDE\plugins\ on Windows (you may need to make this directory yourself beforehand). Restart the IDE.