diff --git a/src/nvfp4_megamoe_kernel/nvfp4_mega_moe.py b/src/nvfp4_megamoe_kernel/nvfp4_mega_moe.py
index 881ac113..87a50976 100644
--- a/src/nvfp4_megamoe_kernel/nvfp4_mega_moe.py
+++ b/src/nvfp4_megamoe_kernel/nvfp4_mega_moe.py
@@ -30,15 +30,18 @@ def unpack_ue4m3_u32(x_u32):
     """Unpack uint32 packed UE4M3 scales to float8_e4m3fn.
     
     Each uint32 contains 4 UE4M3 values packed in bits [0:8], [8:16], [16:24], [24:32].
+    Must use bit reinterpret (view), NOT value cast (to) — byte 0x3F is the float8
+    whose bits are 0x3F (~0.984), NOT the integer 63.
     """
     x_u32 = x_u32.contiguous()
     M, N = x_u32.shape
+    # Extract 4 bytes as uint8, then bit-reinterpret to float8_e4m3fn
+    b0 = (x_u32 & 0xFF).to(torch.uint8).view(torch.float8_e4m3fn)
+    b1 = ((x_u32 >> 8) & 0xFF).to(torch.uint8).view(torch.float8_e4m3fn)
+    b2 = ((x_u32 >> 16) & 0xFF).to(torch.uint8).view(torch.float8_e4m3fn)
+    b3 = ((x_u32 >> 24) & 0xFF).to(torch.uint8).view(torch.float8_e4m3fn)
+    # Interleave into (M, N*4)
     out = torch.empty(M, N * 4, dtype=torch.float8_e4m3fn, device=x_u32.device)
-    # Vectorized unpack: extract 4 bytes from each uint32
-    b0 = (x_u32 & 0xFF).to(torch.int32).to(torch.float8_e4m3fn)
-    b1 = ((x_u32 >> 8) & 0xFF).to(torch.int32).to(torch.float8_e4m3fn)
-    b2 = ((x_u32 >> 16) & 0xFF).to(torch.int32).to(torch.float8_e4m3fn)
-    b3 = ((x_u32 >> 24) & 0xFF).to(torch.int32).to(torch.float8_e4m3fn)
     out[:, 0::4] = b0
     out[:, 1::4] = b1
     out[:, 2::4] = b2