Q4NX is FastFlowLM's native packed-quantization format - in the case of GPT-OSS a rearranged Q4_1-Q4NX layout tuned for the NPU matrix engine's tile sizes and memory access patterns. It is not a GGUF file and it does not run on llama.cpp or Ollama; it is meant exclusively for the FastFlowLM engine on AMD Ryzen AI NPUs.

Requirements

FastFlowLM >= 0.9.45 (flm CLI)
AMD Ryzen AI processor with XDNA2 (NPU2) - Strix Point / Ryzen AI 300 series or later
Linux with the XRT NPU stack installed
~16 GB of unified system memory (Q4NX weights + activations + KV cache)

Files

File	Purpose
model.q4nx	Quantized Q4NX weights
config.json	FastFlowLM model configuration
tokenizer.json	Tokenizer
tokenizer_config.json	Special tokens and chat template
chat_template.jinja	Chat template (optional)
flm-add.py	Installer script - registers this model with FastFlowLM

Install and run

This repository works with flm-add, a small installer that copies the model into the FastFlowLM user directory and registers the tag minicpm4.6:0.8b. It never modifies the system FastFlowLM install.

pip install flm-add or uv tool install flm-add

bash

uv tool install flm-add
flm-add Atomic-Germ/GPT-OSS-GPT5.2-Distill-NPU2 --tag gpt5.2-distill:20b --family gpt-oss
FLM_CONFIG_PATH="$HOME/.config/flm/model_list.json" FLM_XCLBIN_PATH="$HOME/.config/flm" flm run gpt5.2-distill:20b

Kernels

FastFlowLM's NPU kernels (xclbins) are closed source and are not shipped in this repository. flm-add.py links the kernels of the official gpt-oss:20b model (GPT-OSS-20B-NPU2), because this model shares the same engine family (gpt-oss) and architecture.

Model

Registry tag: openai-coder-neo:20b
Engine family: gpt-oss
Kernel source: GPT-OSS-20B-NPU2
Context length: 131,072 tokens (from config)
model.q4nx size: 14.45 GB
Base model: DavidAU/OpenAI-gpt-oss-20B-GPT5.1-5.2-DISTILL-Heretic-Uncensored-MXFP4
License: apache-2.0

Original model card

See the upstream model card for training details, benchmarks, and upstream usage. This repository only contains the Q4NX conversion for FastFlowLM.

Upstream card: DavidAU/OpenAI-gpt-oss-20B-GPT5.1-5.2-DISTILL-Heretic-Uncensored-MXFP4