ComfyUI-QwenImageLoraLoader

A ComfyUI custom node for loading and applying LoRA (Low-Rank Adaptation) to Nunchaku Qwen Image models.

This project is based on the fork version of ComfyUI-nunchaku-qwen-lora-suport-standalone.

Source

This LoRA loader was extracted and modified from the fork version:

Original Fork: ComfyUI-nunchaku-qwen-lora-suport-standalone
Extraction: LoRA functionality was extracted from the full fork to create an independent custom node
Integration: Modified to work with the official ComfyUI-nunchaku plugin

Features

NunchakuQwenImageLoraLoader: Load and apply single LoRA to Qwen Image models
NunchakuQwenImageLoraStack: Apply multiple LoRAs with dynamic UI control
Dynamic VRAM Management: Automatic CPU offloading based on available VRAM
LoRA Composition: Efficient LoRA stacking and composition
ComfyUI Integration: Seamless integration with ComfyUI workflows

Installation

Quick Installation (Recommended)

Clone this repository to your ComfyUI custom_nodes directory:

git clone https://github.com/ussoewwin/ComfyUI-QwenImageLoraLoader.git

Ensure you have the official ComfyUI-nunchaku plugin installed (which includes nunchaku as a dependency).
Run the installation script:
- Double-click install_qwen_lora.bat to automatically configure the integration
- This script will automatically modify the ComfyUI-nunchaku __init__.py file
- Restart ComfyUI

Manual Installation

If you prefer manual installation, see INSTALLATION.md for detailed instructions.

Integration with ComfyUI-nunchaku

IMPORTANT: This node requires modification of the official ComfyUI-nunchaku plugin to function properly.

Required Modification

You must modify the __init__.py file in your ComfyUI-nunchaku plugin to import this LoRA loader:

try:
    # Import from the independent ComfyUI-QwenImageLoraLoader
    import sys
    import os
    qwen_lora_path = os.path.join(os.path.dirname(__file__), "..", "ComfyUI-QwenImageLoraLoader")
    if qwen_lora_path not in sys.path:
        sys.path.insert(0, qwen_lora_path)
    
    # Import directly from the file path
    import importlib.util
    spec = importlib.util.spec_from_file_location("qwenimage", os.path.join(qwen_lora_path, "nodes", "lora", "qwenimage.py"))
    qwenimage_module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(qwenimage_module)
    
    NunchakuQwenImageLoraLoader = qwenimage_module.NunchakuQwenImageLoraLoader
    NunchakuQwenImageLoraStack = qwenimage_module.NunchakuQwenImageLoraStack

    NODE_CLASS_MAPPINGS["NunchakuQwenImageLoraLoader"] = NunchakuQwenImageLoraLoader
    NODE_CLASS_MAPPINGS["NunchakuQwenImageLoraStack"] = NunchakuQwenImageLoraStack
    logger.info("Successfully imported Qwen Image LoRA loaders from ComfyUI-QwenImageLoraLoader")
except ImportError:
    logger.exception("Nodes `NunchakuQwenImageLoraLoader` and `NunchakuQwenImageLoraStack` import failed:")

Why This Modification is Required

The independent LoRA loader exists as a separate custom node
The official ComfyUI-nunchaku plugin needs to reference the independent LoRA loader
Standard from ... import ... fails due to different package structures
importlib.util allows direct module loading from file paths

Automated Installation (Recommended)

The batch file install_qwen_lora.bat automatically adds the above code to your ComfyUI-nunchaku __init__.py file:

What the batch file does:
- Automatically detects your ComfyUI installation path
- Backs up the original __init__.py file (creates __init__.py.backup)
- Adds the exact import code shown above to the end of ComfyUI-nunchaku's __init__.py
- Performs error checking to ensure all required files exist
- Provides user feedback throughout the process
Run the installation script:
- Double-click install_qwen_lora.bat to automatically configure the integration
- No manual code editing required - the script handles everything
- Restart ComfyUI after installation
Uninstall if needed:
- Double-click uninstall_qwen_lora.bat to restore the original configuration
- This will restore the backup and remove the integration code

Usage

Available Nodes

NunchakuQwenImageLoraLoader: Single LoRA loader
NunchakuQwenImageLoraStack: Multi LoRA stacker with dynamic UI

Basic Usage

Load your Nunchaku Qwen Image model using Nunchaku Qwen Image DiT Loader
Add either NunchakuQwenImageLoraLoader or NunchakuQwenImageLoraStack node
Select your LoRA file and set the strength
Connect to your workflow

Dynamic UI Control

The NunchakuQwenImageLoraStack node automatically adjusts the number of visible LoRA slots based on the lora_count parameter (1-10).

Features

Easy Installation: Automated installation script included
Automatic Integration: No manual code editing required
Backup & Restore: Automatic backup of original files
Cross-Platform: Works on Windows with batch files
Error Handling: Comprehensive error checking and user feedback
Issue #1 Fixed: Resolved ComfyUI\custom_nodes not found error with improved path detection (thanks to @mcv1234's solution)
Issue #2 Fixed: Fixed UTF-8 encoding error causing SyntaxError: (unicode error) by using PowerShell for proper UTF-8 encoding when writing to __init__.py

Requirements

ComfyUI
ComfyUI-nunchaku plugin (with required modification)
PyTorch
Python 3.10+

Compatibility

This node is designed to work with:

ComfyUI-nunchaku plugin (modified)
Nunchaku Qwen Image models
Standard ComfyUI workflows

Changelog

v1.2.0 (Latest)

Fixed Issue #2: Resolved UTF-8 encoding error that caused SyntaxError: (unicode error) 'utf-8' codec can't decode byte 0x90 in position 0
Reported by: @AHEKOT (GitHub Issue #2)
Special Thanks: This critical bug was discovered and reported by @AHEKOT, who provided detailed error traces and screenshots
Technical Fix: Changed the batch file to use PowerShell for UTF-8 encoding when writing Python code to __init__.py
Root Cause: Windows batch files write in Shift-JIS encoding by default, which causes Python to fail when reading files as UTF-8
Solution: Temporary file creation + PowerShell UTF-8 encoding ensures proper file encoding
Technical Details:
- Changed from direct append (>>) to temp file method
- Uses PowerShell Get-Content and Add-Content with -Encoding UTF8 parameters
- Ensures all Python code is written with proper UTF-8 encoding
Impact: Installation script now works correctly without encoding errors
Community Contribution: This fix was made possible by @AHEKOT's thorough bug reporting and error documentation

v1.1.0

Fixed Issue #1: Resolved "ComfyUI\custom_nodes not found" error reported by @mcv1234
Special Thanks: This fix was implemented based on the excellent solution provided by @mcv1234 in the GitHub issue
Improved Path Detection: Replaced unreliable wildcard search with relative path detection using script directory (solution by @mcv1234)
Enhanced Error Messages: Added clear directory structure guidance and expected folder layout
Better User Experience: More reliable installation process with comprehensive error checking
Technical Details:
- Changed from dir /s /b /ad "*ComfyUI\custom_nodes" to relative path calculation (as suggested by @mcv1234)
- Uses %~dp0 (script directory) to calculate ComfyUI root with ..\.. navigation
- Added validation for custom_nodes folder existence
- Improved error messages with expected directory structure display
Community Contribution: This improvement was made possible by the community feedback and solution provided by @mcv1234

v1.0.0

Initial release with LoRA loading functionality
Automated installation scripts
Integration with ComfyUI-nunchaku

License

This project is licensed under the MIT License.