diff --git a/Cargo.toml b/Cargo.toml
index bb64cc7..f95733d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,7 @@ keywords = ["deep-learning", "language", "model", "rwkv"]
 license = "MIT OR Apache-2.0"
 name = "web-rwkv"
 repository = "https://github.com/cryscan/web-rwkv"
-version = "0.8.4"
+version = "0.8.5"
 
 [dependencies]
 ahash = "0.8"
diff --git a/src/context.rs b/src/context.rs
index 6f8dece..3141826 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -344,7 +344,15 @@ impl ContextInternal {
 
         let data = {
             let map = slice.get_mapped_range();
-            map.to_vec().into_boxed_slice()
+            let len = map.len();
+            let size = std::mem::size_of::<u32>();
+            let data = vec![0u32; (len + size - 1) / size].into_boxed_slice();
+            unsafe {
+                let data = Box::leak(data);
+                let data: &mut [u8] = bytemuck::cast_slice_mut(data);
+                data.copy_from_slice(&map);
+                Box::from_raw(data)
+            }
         };
         buffer.unmap();
         data
diff --git a/src/tensor/mod.rs b/src/tensor/mod.rs
index d0a6c5f..281d93d 100644
--- a/src/tensor/mod.rs
+++ b/src/tensor/mod.rs
@@ -428,7 +428,7 @@ impl<T: Scalar> TensorInto<TensorGpu<T, ReadWrite>> for TensorGpu<T, ReadWrite>
     fn transfer_into(self, context: &Context) -> Self {
         match context {
             context if context == &self.context => self,
-            _ => self.back_local().transfer_into(context),
+            _ => self.back_in_place().transfer_into(context),
         }
     }
 }
@@ -474,7 +474,7 @@ impl<T: Scalar, K: Kind> TensorReshape for TensorGpu<T, K> {
 
 impl<T: Scalar, K: Kind> TensorGpu<T, K> {
     #[cfg(not(target_arch = "wasm32"))]
-    pub fn back_local(&self) -> TensorCpu<T> {
+    pub fn back_in_place(&self) -> TensorCpu<T> {
         use crate::context::ContextEvent;
 
         let context = &self.context;
@@ -495,10 +495,8 @@ impl<T: Scalar, K: Kind> TensorGpu<T, K> {
         });
         let data = receiver.blocking_recv().unwrap();
         let data = unsafe {
-            let len = data.len() / std::mem::size_of::<T>();
             let data = Box::leak(data);
-            let data = data.as_mut_ptr() as *mut T;
-            let slice = core::slice::from_raw_parts_mut(data, len);
+            let slice = bytemuck::cast_slice_mut::<_, T>(data);
             Box::from_raw(slice)
         };
         let data = data.into_vec().into();
@@ -534,10 +532,8 @@ impl<T: Scalar, K: Kind> TensorGpu<T, K> {
         });
         let data = receiver.await.unwrap();
         let data = unsafe {
-            let len = data.len() / std::mem::size_of::<T>();
             let data = Box::leak(data);
-            let data = data.as_mut_ptr() as *mut T;
-            let slice = core::slice::from_raw_parts_mut(data, len);
+            let slice = bytemuck::cast_slice_mut::<_, T>(data);
             Box::from_raw(slice)
         };
         let data = data.into_vec().into();
diff --git a/src/tensor/ops.rs b/src/tensor/ops.rs
index bca9567..89a953f 100644
--- a/src/tensor/ops.rs
+++ b/src/tensor/ops.rs
@@ -2457,7 +2457,7 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let x_host = x_dev.back_local().to_vec();
+        let x_host = x_dev.back_in_place().to_vec();
 
         let mut ans = vec![];
         for x in &x.into_iter().chunks(C) {
@@ -2524,8 +2524,8 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let x_host = x_dev.back_local().to_vec();
-        // let s_host = s_dev.back_local().to_vec();
+        let x_host = x_dev.back_in_place().to_vec();
+        // let s_host = s_dev.back_in_place().to_vec();
 
         // test recenter and rms norm
         let shape = Shape::new(C, T, B, 1);
@@ -2541,7 +2541,7 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let x_rms_host = x_dev.back_local().to_vec();
+        let x_rms_host = x_dev.back_in_place().to_vec();
 
         let mut ans = vec![];
         // let mut ans_stats = vec![];
@@ -2669,7 +2669,7 @@ mod tests {
         // profiler.resolve_queries(&mut encoder);
         context.queue.submit(Some(encoder.finish()));
 
-        let output_host = output_dev.back_local();
+        let output_host = output_dev.back_in_place();
         let output_host = Vec::from(output_host);
 
         // profiler.end_frame().unwrap();
@@ -2797,8 +2797,8 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let matrix_u8_host = matrix_u8_dev.back_local().to_vec();
-        let output_host = output_dev.back_local().to_vec();
+        let matrix_u8_host = matrix_u8_dev.back_in_place().to_vec();
+        let output_host = output_dev.back_in_place().to_vec();
 
         // let mut truth = vec![0.0; output_host.len()];
         // for token in 0..T {
@@ -2971,9 +2971,9 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let matrix_u4_host = matrix_u4_dev.back_local().to_vec();
-        let absmax_host = absmax_dev.back_local().to_vec();
-        let output_host = output_dev.back_local().to_vec();
+        let matrix_u4_host = matrix_u4_dev.back_in_place().to_vec();
+        let absmax_host = absmax_dev.back_in_place().to_vec();
+        let output_host = output_dev.back_in_place().to_vec();
 
         let mut truth = vec![0.0; output_host.len()];
         for token in 0..T {
@@ -3070,7 +3070,7 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let output_host = output.back_local();
+        let output_host = output.back_in_place();
         let output_host = Vec::from(output_host);
 
         assert_eq!(
@@ -3107,7 +3107,7 @@ mod tests {
         drop(pass);
         context.queue.submit(Some(encoder.finish()));
 
-        let output_host = output.back_local();
+        let output_host = output.back_in_place();
         let output_host: Vec<f32> = Vec::from(output_host);
 
         assert_eq!(
diff --git a/src/tensor/serialization.rs b/src/tensor/serialization.rs
index 5149e22..46f9ad0 100644
--- a/src/tensor/serialization.rs
+++ b/src/tensor/serialization.rs
@@ -60,7 +60,7 @@ impl<T: Scalar + Serialize, K: Kind> Serialize for TensorGpu<T, K> {
     where
         S: serde::Serializer,
     {
-        TensorBlob::from(self.back_local()).serialize(serializer)
+        TensorBlob::from(self.back_in_place()).serialize(serializer)
     }
 }