Tech Feb 6, 2026 6 min UltraFlux-v1 - a native 4K image generation model based on FLUX.1-dev Technical details of UltraFlux-v1, a model that pushes FLUX.1-dev into native 4K generation. It covers the differences from Z-Image and FLUX.2 Klein, its RoPE extensions and VAE improvements, and practical caveats. AI Image Generation FLUX 4K
