---
id: pr-vllm-21499
repo: vllm-project/vllm
pr: 21499
title: '[NVIDIA] Fix Llama4 Scout FP4 functionality issues'
author: nvpohanh
date: '2025-07-30'
url: https://github.com/vllm-project/vllm/pull/21499
source_category: upstream-code
architectures:
- sm100
tags:
- fp4
- kernel-fusion
- moe
- quantization
techniques:
- kernel-fusion
hardware_features:
- fp4
kernel_types:
- moe
- quantization
languages:
- python
captured_at: '2026-04-27'
status: merged
merge_sha: ff08e51940a77d2dd14a6c512bec4613d060b4fa
inclusion_reason: kernel file changes
changed_paths:
- vllm/model_executor/layers/fused_moe/layer.py
- vllm/model_executor/layers/quantization/modelopt.py
- vllm/model_executor/models/llama4.py
head_ref_oid: edfd4f9548311ba7f009fa478e8ae3b12c2afd79
artifact_dir: evidence/pull-bundles/vllm/gh-21499
---
# [NVIDIA] Fix Llama4 Scout FP4 functionality issues

- Repository: `vllm-project/vllm`
- PR: [21499](https://github.com/vllm-project/vllm/pull/21499)
- Decision: `kernel file changes`
- Reason: kernel file changes

## Changed Paths

- `vllm/model_executor/layers/fused_moe/layer.py`
- `vllm/model_executor/layers/quantization/modelopt.py`
- `vllm/model_executor/models/llama4.py`

## Evidence Bundle

`evidence/pull-bundles/vllm/gh-21499`
