---
base_model: z-lab/Qwen3.5-4B-DFlash
tags:
- gguf
- dflash
- speculative-decoding
- draft-model
- qwen3.5
library_name: gguf
---

# Qwen3.5-4B-DFlash — Q4_0 GGUF (draft model)

A **Q4_0 GGUF** of the [`z-lab/Qwen3.5-4B-DFlash`](https://huggingface.co/z-lab/Qwen3.5-4B-DFlash)
block-diffusion **draft model** for [DFlash](https://github.com/z-lab/dflash) speculative
decoding with the **Qwen3.5-4B** target. This is not a standalone language model — it must be
paired with the Qwen3.5-4B target in a DFlash-capable llama.cpp server.

## Files

| File | Size (bytes) | SHA256 |
| --- | ---: | --- |
| `qwen35-4b-dflash-Q4_0.gguf` | 367,939,840 | `2772878B6B2B4E607C42BFCEE5A429B54BE27F7A57E86A3108E9E437CB5C79FF` |

69 tensors total: 43 2-D weight tensors are Q4_0, the remaining 26 (norms, etc.) are F32.

## Provenance

- **Source:** `z-lab/Qwen3.5-4B-DFlash`, HF revision `9a1996ccf887b79ab3af4fcbf8c1d1f4b5658bcf`
  (`model.safetensors` SHA256 `1EB221D36ABB13A5F1B972F8D031A9723FAD8CBB7D275ABE548B60E77577EB42`).
- **Conversion:** upstream `llama.cpp` `convert_hf_to_gguf.py` with the DFlash support merged in
  [ggml-org/llama.cpp#22105](https://github.com/ggml-org/llama.cpp/pull/22105), sourcing the
  tokenizer from the Qwen3.5-4B target via `--target-model-dir`. safetensors → BF16 GGUF →
  `llama-quantize Q4_0`.
- The BF16 intermediate is 1,279,873,280 bytes.

## Architecture / GGUF metadata

- `general.architecture = dflash`
- 6 layers: **5 `sliding_attention` + 1 `full_attention`** (`sliding_window = 4096`)
- hidden 2560, FFN 9216, 32 Q heads / 8 KV heads, head dim 128
- `dflash.block_size = 16`
- `dflash.target_layers = [2, 6, 10, 14, 18, 22, 26, 30]` (llama.cpp layer-input semantics;
  the source `dflash_config.target_layer_ids` are `[1, 5, 9, 13, 17, 21, 25, 29]`)
- `tokenizer.ggml.mask_token_id = 248077`, vocab size 248320 (shares the Qwen3.5-4B vocab)

The draft is only the DFlash core; at runtime it borrows the target's token embedding and
tied output projection.

## Usage (sketch)

Run against the Qwen3.5-4B target in a DFlash-capable `llama.cpp` server, e.g.:

```
llama-server \
  -m Qwen3.5-4B-Q4_0.gguf \
  --spec-draft-model qwen35-4b-dflash-Q4_0.gguf \
  --spec-type draft-dflash --spec-draft-n-max 7
```

DFlash speculative decoding is not part of stock upstream `llama.cpp` runtime; use a build
with DFlash runtime support.

## License

Inherits the terms of the base model — see
[`z-lab/Qwen3.5-4B-DFlash`](https://huggingface.co/z-lab/Qwen3.5-4B-DFlash).