diff --git a/src/nvfp4_megamoe_kernel/cutlass_nvfp4_gemm/cutlass_nvfp4_gemm.cu b/src/nvfp4_megamoe_kernel/cutlass_nvfp4_gemm/cutlass_nvfp4_gemm.cu
index fb3e05cf..bbed2662 100644
--- a/src/nvfp4_megamoe_kernel/cutlass_nvfp4_gemm/cutlass_nvfp4_gemm.cu
+++ b/src/nvfp4_megamoe_kernel/cutlass_nvfp4_gemm/cutlass_nvfp4_gemm.cu
@@ -122,7 +122,15 @@ __global__ void remap_sf_to_cutlass_kernel(
     int k_group = src_idx % K_sf;
     int k_elem = k_group * SFVecSize;
 
-    dst[layout_sf(m, k_elem)] = src[src_idx];
+    // Construct a coordinate matching the layout's top-level mode structure.
+    // The layout shape from tile_to_shape(SfAtom{}, make_shape(MN, K), Step<_2, _1>)
+    // has two top-level modes:
+    //   Mode 0 (M): shape (32, 4) — the SfAtom's M sub-structure
+    //   Mode 1 (K): int — the K dimension
+    // For mode 0, we decompose m into (inner_m, sub_m) = (m / 4, m % 4)
+    // For mode 1, we pass k_elem directly.
+    auto coord = cute::make_tuple(cute::make_tuple(m / 4, m % 4), k_elem);
+    dst[layout_sf(coord)] = src[src_idx];
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////////////