Complete proposed changes for loading, converting, and testing Qwen/Qwen3.8-27B-FP8 in mlx-vlm, based on Blaizzy/mlx-vlm commit 74b740b9bb1a1248e4b7b12b3b1ba7cae9c21e9f.
The Qwen checkpoint stores projection weights as E4M3 bytes with arbitrary BF16 inverse scales on a 128×128 block grid. Native MLX MXFP8 instead uses E8M0 scales per output row and per 32-value group.
DeepSeek V4 can losslessly repack its FP8 tensors because its source scales are already UE8M0-compatible. Qwen cannot use that byte reinterpretation. Its source blocks must be reconstructed and immediately requantized into native MLX MXFP8.