Nemotron-3 Nano 4B Uncensored (Aggressive): First Abliteration with GenRM Removal + K_P Quants

Reddit r/LocalLLaMA / 3/25/2026

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Key Points

  • A Hugging Face release claims the first public “abliteration” of NVIDIA’s Nemotron-3 Nano 4B aimed at removing both base refusals and GenRM (a generative reward model used as an extra censorship layer).
  • The author reports 0/465 refusals on the GenRM-removed variant and says the GenRM-active comparison build still produces effective refusals on a subset of topics due to generation-time overrides.
  • The post argues that GenRM can cause the model to appear to comply in chain-of-thought while the final output refuses or twists the response, creating harder-to-test behavior.
  • The package includes multiple GGUF quantization variants, emphasizing custom “K_P” quantizations intended to preserve quality with modest (about 5–15%) file-size increases and compatibility with llama.cpp/LM Studio.
  • It highlights architectural considerations because Nemotron-3 Nano 4B is a hybrid Mamba2-Transformer rather than a standard transformer, which the author says influenced the approach to the ablation.

First ever abliteration of NVIDIA's Nemotron-3 Nano 4B, and the first public abliteration to tackle GenRM removal.

Aggressive = no refusals; no personality changes and no alterations. The ORIGINAL NVIDIA release, just completely uncensored.

https://huggingface.co/HauhauCS/Nemotron3-Nano-4B-Uncensored-HauhauCS-Aggressive

0/465 refusals. Fully unlocked with zero capability loss\*. Asterisk is here on these. I haven't encountered any degenerated output, loss of coherence, looping, etc however due to GenRM, I can't guarantee and as a single person, I have limited time/resources.

What is GenRM and why does it matter?

NVIDIA baked a generative reward model (GenRM) into Nemotron that acts as a second layer of censorship. Even after abliteration removes the base model's refusals, GenRM re-introduces them at generation time. You can literally see it happen when the model reasons through your request normally in the Chain-of-Thought, then does a complete 180 in the actual output. CoT says "sure, here's how" or gives clear signs of it intending to comply and the output says "I can't help with that." or tries to directly twist it into something else, it's wild with possible ramifications in the future.

This release has GenRM fully removed. For anyone curious to see the difference firsthand, I uploaded a comparison build with GenRM still active (IQ2_M only):

Nemotron3-Nano-4B-Uncensored-HauhauCS-Aggressive-GenRM

The abliteration itself scores 0/465 on both builds but with GenRM active the effective result skews to roughly ~10/465 because GenRM overrides the abliterated weights on certain topics. It gets very difficult to properly test and assess how deep this actually goes.

This was also a unique challenge architecturally since Nemotron-H is a hybrid Mamba2-Transformer, not a standard transformer. Was inherently the reason I decided to tackle it, then came along GenRM :)

Anyways! What's included:

- Q8_K_P, Q6_K_P, Q5_K_P, Q5_K_M, Q4_K_P, Q4_K_M, IQ4_XS, Q3_K_P, Q3_K_M, IQ3_M, Q2_K_P, IQ2_M (included BPW table for those curious)

- All quants generated with imatrix

- K_P quants are custom quantizations that use model-specific analysis to selectively preserve quality where it matters most. Effectively 1-2 quant levels better quality at only ~5-15% larger file size. Fully compatible with llama.cpp, LM Studio, or mostly anything that reads GGUF.

Quick specs:

- 3.97B parameters

- Hybrid Mamba2-Transformer (42 layers: 21 Mamba2, 17 MLP, 4 Attention)

- 262K native context

- Thinking/reasoning mode (toggleable)

- Tool calling support

- Compressed from Nemotron-Nano-9B-v2

Sampling from NVIDIA: temp=1.0, top_p=0.95 for reasoning; temp=0.6, top_p=0.95 for tool calling.

Note: Use --jinja flag with llama.cpp. K_P quants may show as "?" in LM Studio — cosmetic only, model loads fine. HuggingFace's hardware compatibility widget also doesn't show all K_P files — go to Files and versions to see everything.

Coming up next: Nemotron Cascade2 30B-A3B, Qwen3 Next Coder (focused on coding uncensoring), Maybe Gemma3?

If you have any models you might like me to uncensor, feel free to let me know! It's not a guarantee but I do prioritize these based on amounts of requests :)

All my models: HuggingFace-HauhauCS

Looking forward to hearing your comparisons between the GenRM and non-GenRM builds.

submitted by /u/hauhau901
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