diff --git a/studio/backend/core/inference/diffusion_families.py b/studio/backend/core/inference/diffusion_families.py
index 68e7f2f406..25ae53c9f7 100644
--- a/studio/backend/core/inference/diffusion_families.py
+++ b/studio/backend/core/inference/diffusion_families.py
@@ -339,6 +339,14 @@ _FAMILIES: tuple[DiffusionFamily, ...] = (
     # HunyuanImage-3.0, which stays excluded above: 2.1 has a real diffusers pipeline.
     DiffusionFamily(
         name = "hunyuanimage-2.1",
+        # Hosted checkpoints, verified bit-identical to on-the-fly quantize (the family's
+        # guider pipeline is not run-to-run deterministic, so same-seed LPIPS vs bf16 blends
+        # trajectory divergence with harness noise; per-case hard checks pass and the drift is
+        # compositional, reviewed visually).
+        prequant_repos = (
+            ("int8", "unsloth/HunyuanImage-2.1-FP8"),
+            ("fp8", "unsloth/HunyuanImage-2.1-FP8"),
+        ),
         pipeline_class = "HunyuanImagePipeline",
         transformer_class = "HunyuanImageTransformer2DModel",
         base_repo = "hunyuanvideo-community/HunyuanImage-2.1-Diffusers",
diff --git a/studio/backend/tests/test_diffusion_more_families.py b/studio/backend/tests/test_diffusion_more_families.py
index b9515df65d..724cd660d2 100644
--- a/studio/backend/tests/test_diffusion_more_families.py
+++ b/studio/backend/tests/test_diffusion_more_families.py
@@ -191,6 +191,15 @@ def test_hunyuanimage21_generation_defaults():
     ) == (50, 3.25)
 
 
+def test_hunyuanimage21_prequant_wiring():
+    # Hosted int8/fp8 checkpoints, verified bit-identical to on-the-fly quantize.
+    from core.inference.diffusion_families import family_prequant_repo
+
+    fam = detect_family("hunyuanvideo-community/HunyuanImage-2.1-Diffusers")
+    for scheme in ("int8", "fp8"):
+        assert family_prequant_repo(fam, scheme) == "unsloth/HunyuanImage-2.1-FP8"
+
+
 def test_hunyuanimage21_bf16_component_table_present():
     fam = detect_family("hunyuanvideo-community/HunyuanImage-2.1-Diffusers")
     sizes = family_bf16_components_gb(fam)