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Mainsail — K2 Plus

Mainsail is an alternative web interface to Fluidd. It is not pre-installed on the K2 Plus but can be added by the Helper Script on port 4409, running alongside the stock Fluidd installation.


Installation

From the helper script menu, select option 9 — Mainsail (port 4409).

The script will: 1. Download the latest Mainsail release 2. Install static files to /usr/share/mainsail/ 3. Add a new nginx server block for port 4409 4. Restart nginx


Access Mainsail

After installation:

http://<printer-ip>:4409

Update / Repair Mainsail

Run the helper script and select option 9 again. If Mainsail is already installed you will be offered:

  • Update — download and install the latest release
  • Repair — re-download and reinstall
  • Restore nginx block only — restore port 4409 without re-downloading

Fluidd vs Mainsail

Both interfaces connect to the same Moonraker instance and offer equivalent functionality. Key differences:

Feature Fluidd Mainsail
Port 4408 (pre-installed) 4409 (helper script)
UI style Clean, dashboard-focused Feature-rich, more settings
Timelapse UI Via plugin Built-in
Spoolman Via plugin Built-in

You can use both simultaneously — they share the same Moonraker backend and printer state.


Mainsail Configuration

Mainsail stores its configuration in mainsail.cfg. After installation, add this include to your printer.cfg if you want Mainsail-specific features:

# From SSH
echo "[include mainsail.cfg]" >> /mnt/UDISK/printer_data/config/printer.cfg

Or add it via the Fluidd/Mainsail editor.


Camera Setup

Camera support is installed separately via option 11) Camera Support for Fluidd and Mainsail. Once installed, the camera feed appears automatically in the Mainsail dashboard after boot — no manual configuration required. See the Camera Support page for details.