diff --git a/studio/install_llama_prebuilt.py b/studio/install_llama_prebuilt.py
index 77d0905020..b0af64fc8d 100644
--- a/studio/install_llama_prebuilt.py
+++ b/studio/install_llama_prebuilt.py
@@ -237,13 +237,16 @@ _MAX_PROBE_CUDA_MAJOR = 19
 # Last ggml-org release whose Windows win-cuda-13 build is still sub-13.3
 # (cuda-13.1, b9360, 2026-05-27). Upstream bumped win-cuda-13 to 13.3 at b9365
 # and now ships only cuda-12.4 + cuda-13.3. cuda-12.4 predates Blackwell (ggml
-# compiles sm_120 only at toolkit >= 12.8), so a Blackwell host on a 13.1/13.2
+# compiles sm_120 only at toolkit >= 12.8), so a Blackwell host on a 13.0/13.1/13.2
 # driver is gated off 13.3 and would drop to a CPU-only 12.4 build. b9360 is
 # immutable, so we pin its cuda-13.1 build (plus paired cudart) as a GPU
 # fallback for exactly those hosts. See unslothai/unsloth#5887.
 _PINNED_BLACKWELL_FALLBACK_TAG = "b9360"
 _PINNED_BLACKWELL_FALLBACK_RUNTIME = "13.1"
-_PINNED_BLACKWELL_DRIVER_FLOOR = (13, 1)
+# Floor at 13.0: b9360 ships native sm_120a SASS (no PTX/JIT) and a bundled
+# cuda-13.1 cudart, both of which run on a CUDA 13.0 r580+ driver via CUDA
+# minor-version compatibility, so the mainstream 13.0 Blackwell branch is covered.
+_PINNED_BLACKWELL_DRIVER_FLOOR = (13, 0)
 _BLACKWELL_MIN_SM = 120
 # ggml compiles Blackwell sm_120 only at toolkit >= 12.8, so an in-release
 # windows-cuda build at or above this already covers Blackwell and makes the
diff --git a/tests/studio/install/test_selection_logic.py b/tests/studio/install/test_selection_logic.py
index 78aa9c480e..8cb53d1aeb 100644
--- a/tests/studio/install/test_selection_logic.py
+++ b/tests/studio/install/test_selection_logic.py
@@ -2021,7 +2021,7 @@ class TestWindowsCudaAttempts:
 
 
 class TestPinnedBlackwellCudaFallback:
-    """A Blackwell host on a 13.1/13.2 driver, gated off the in-release 13.3
+    """A Blackwell host on a 13.0/13.1/13.2 driver, gated off the in-release 13.3
     build, gets the pinned immutable b9360 cuda-13.1 GPU build instead of the
     CPU-only cuda-12.4 drop. The pin is dormant for everyone else."""
 
@@ -2072,15 +2072,19 @@ class TestPinnedBlackwellCudaFallback:
         # Ada/Hopper run the cuda-12.4 build fine; the pin must not fire.
         assert _pinned_windows_cuda_fallback(self._win_host((13, 1), [sm]), []) is None
 
-    def test_pin_not_offered_to_driver_13_0(self):
-        # 13.0 cannot run the 13.1 build (forward minor); residual CPU gap.
+    def test_pin_offered_for_driver_13_0(self):
+        # b9360 is native sm_120a SASS (no JIT) and ships a cuda-13.1 cudart,
+        # both of which run on a 13.0 r580+ driver via CUDA minor-version
+        # compatibility. 13.0 is the mainstream Blackwell branch, so it must fire.
         assert (
-            _pinned_windows_cuda_fallback(self._win_host((13, 0), ["120"]), []) is None
+            _pinned_windows_cuda_fallback(self._win_host((13, 0), ["120"]), [])
+            is not None
         )
 
     def test_pin_not_offered_below_floor(self):
+        # 12.x predates Blackwell entirely; the pin stays dormant below 13.0.
         assert (
-            _pinned_windows_cuda_fallback(self._win_host((12, 8), ["120"]), []) is None
+            _pinned_windows_cuda_fallback(self._win_host((12, 9), ["120"]), []) is None
         )
 
     def test_pin_not_offered_without_driver(self):