diff --git a/dsv4/kernels/router/nvfp4_fused_router_kernel.py b/dsv4/kernels/router/nvfp4_fused_router_kernel.py
index 2973403d..f7243d33 100644
--- a/dsv4/kernels/router/nvfp4_fused_router_kernel.py
+++ b/dsv4/kernels/router/nvfp4_fused_router_kernel.py
@@ -1046,11 +1046,10 @@ def run_nvfp4_fused_router(
     device = hidden_states.device
 
     # Quantize activation to NVFP4
-    act_nvfp4, act_sf, _gsa, _gsb = quantize_activation_nvfp4(
-        hidden_states, sf_vec_size=sf_vec_size)
-    # Override global scales with provided values
-    act_gsa = gsa if gsa is not None else _gsa
-    act_gsb = gsb_val
+    # Compute activation global scale
+    act_amax = float(hidden_states.float().abs().max()) + 1e-8
+    act_gs = act_amax / (6.0 * 448.0)  # max E2M1 magnitude * E4M3 max
+    act_nvfp4, act_sf = quantize_activation_nvfp4(hidden_states, act_gs)
 
     def to_cute(t):
         ct = cutlass_torch.from_dlpack(t)