FLUX.2 in ComfyUI — Compatibility Guide

Status: Native ComfyUI support confirmed as of June 2026.
See references/flux2-setup.md for the complete reproduction recipe, model downloads, and workflow JSON.

The Problem (Historical)

FLUX.2-klein (9B) uses an 8B Qwen3-VL text embedder, replacing the CLIP-L + T5XXL combo used by FLUX.1. Early ComfyUI versions (pre-mid 2026) lacked native nodes for FLUX.2, forcing users to:

Use the diffusers Flux2KleinPipeline instead, or
Wait for community custom nodes

This is no longer necessary. ComfyUI now includes:

CLIPType.FLUX2 enum (line 1299 in comfy/sd.py)
Flux2 model class (line 1057 in comfy/model_base.py)
EmptyFlux2LatentImage node (128-channel latents)
Flux2Scheduler node (mu-snr shifted timesteps)
Flux2TEModel text encoder wrapper with Qwen3VL support
KleinTokenizer / KleinTokenizer8B tokenizers

Error Signature → Fix Mapping

Error	Cause	Fix
`mat1 and mat2 shapes cannot be multiplied (512x4096 and 12288x4096)`	Using CLIP-L+T5XXL with FLUX.2 UNet	Load `Qwen3VL-8B-Instruct-Q4_K_M.gguf` via `CLIPLoaderGGUF` with `"type": "flux2"`
`expected input[1, 128, 32, 32] to have 16 channels, but got 128 channels instead`	Using FLUX.1 VAE (`ae.safetensors`)	Use `taef2` or `flux2_vae.safetensors`
`HIP error: invalid device function`	ROCm gfx1150 without override	`export HSA_OVERRIDE_GFX_VERSION=11.0.0`

Required Models

Component	File	~Size	Source
UNet (GGUF)	`flux-2-klein-9b-Q4_K_S.gguf`	5.4 GB	`unsloth/FLUX.2-klein-9B-GGUF`
Text Encoder	`Qwen3VL-8B-Instruct-Q4_K_M.gguf`	4.7 GB	`Qwen/Qwen3-VL-8B-Instruct-GGUF`
VAE (fast)	`taef2` encoder+decoder `.pth`	5 MB	`madebyollin/taesd` (GitHub)
VAE (full)	`flux2_vae.safetensors`	160 MB	`black-forest-labs/FLUX.2-klein-9B` (gated)

FLUX.1 and FLUX.2 are NOT component-compatible. Do not mix:

❌ FLUX.2 UNet + FLUX.1 CLIP/T5
❌ FLUX.2 latents + FLUX.1 VAE (ae.safetensors)
❌ EmptyLatentImage with FLUX.2 (needs EmptyFlux2LatentImage)

Workflow Differences (FLUX.1 vs FLUX.2)

// FLUX.1 — two CLIP loaders + shared VAE
{"2": {"inputs": {"clip_name1": "t5xxl_fp8_e4m3fn.safetensors", "clip_name2": "clip_l.safetensors", "type": "flux"}, "class_type": "DualCLIPLoaderGGUF"}}
{"4": {"inputs": {"width": 1024, "height": 1024, "batch_size": 1}, "class_type": "EmptyLatentImage"}}
{"3": {"inputs": {"vae_name": "ae.safetensors"}, "class_type": "VAELoader"}}

// FLUX.2 — single Qwen3 CLIP + TAEF2 VAE + 128-channel latent
{"2": {"inputs": {"clip_name": "Qwen3VL-8B-Instruct-Q4_K_M.gguf", "type": "flux2"}, "class_type": "CLIPLoaderGGUF"}}
{"4": {"inputs": {"width": 1024, "height": 1024, "batch_size": 1}, "class_type": "EmptyFlux2LatentImage"}}
{"3": {"inputs": {"vae_name": "taef2"}, "class_type": "VAELoader"}}

Verified E2E Results (gfx1150, ROCm 6.2)

Pipeline	Res	Steps	Time	Status
FLUX.1-dev Q4_K_S + CLIP/T5 + ae.safetensors	512×512	4	~46s	✅
FLUX.2-klein Q4_K_S + Qwen3VL Q4_K_M + taef2	1024×1024	4	~110s	✅

References

Full setup recipe: references/flux2-setup.md
Unsloth GGUF repo: https://huggingface.co/unsloth/FLUX.2-klein-9B-GGUF
Qwen3VL GGUF repo: https://huggingface.co/Qwen/Qwen3-VL-8B-Instruct-GGUF
BFL blog: https://bfl.ai/blog/flux2-klein-towards-interactive-visual-intelligence
TAEF2 source: https://github.com/madebyollin/taesd

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