FreeU_V2_motorway_edition

FreeU_V2 is the sequel nobody asked for and some people swear by: the same "boost low frequencies, suppress high frequencies" detail patch as the original FreeU, but with one genuinely smarter mechanism. Where V1 multiplies the backbone features by a constant, V2 first normalizes each feature map by its spatial variance, then scales - so it boosts strong features less and weak ones more, instead of slapping the same gain on everything. It's a gentler, more selective sharpening.

This is the Motorway-ed version from agilly1989/ComfyUI_agilly1989_motorway: the patch logic is unchanged, but the model is read from a key on the pipe and the patched model is written back to a key.

The inputs that matter

• b1 (default 1.3) and b2 (default 1.4) - backbone (low-frequency) boost at the two patched depths. Notice the defaults are higher than V1's 1.1/1.2, because the adaptive normalization lets it push harder without cooking the image.
• s1 (default 0.9) and s2 (default 0.2) - skip-connection (high-frequency) suppression. Same shape as V1.
• INPUT_model_key (default model) and OUTPUT_MODEL_key (default MODEL) - the key traffic: read the base model, write the patched one.

Output is the MOTORWAY pipe.

V1 vs V2

Both are SD 1.5/SDXL-era tools, and the honest summary from the FreeU article applies to both: the patch targets U-Net block layouts, so it's a real tool on classic checkpoints and increasingly a no-op on modern flow-matching transformers. Between the two, V2 is the safer default if you're going to try one - the variance-adaptive scaling means fewer "why is everything an oil painting" failures at the same settings. The community's general read settled on V2 being the better-tempered sibling, and V1 living on mostly out of nostalgia and muscle memory.

One thing to watch: on some GPUs the Fourier filter inside both FreeU variants can throw a device error, and the node silently falls back to running that filter on the CPU - slower, but it still works. If you see a one-time "switching to CPU" warning in the console, that's FreeU, and it's expected behavior, not a crash.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

Restart ComfyUI, or install via ComfyUI Manager under "ComfyUI_agilly1989_motorway." No extra dependencies.

Standing pack caveat: v1.1.7's pyproject.toml reads "HOTFIX - REMOVED MONKEYPATCH AND GENERATED NODES," with the generated clones commented out of __init__.py. Core Motorway nodes work; the _motorway_edition clones may not be in your menu until the author re-enables them. If it's missing, core FreeU_V2 is the identical patch, and a ramp can get its output onto the bus by hand.