diff --git a/wgpu-hal/src/metal/device.rs b/wgpu-hal/src/metal/device.rs
index 02ef3bffa35..234b9cee9f0 100644
--- a/wgpu-hal/src/metal/device.rs
+++ b/wgpu-hal/src/metal/device.rs
@@ -521,6 +521,14 @@ impl crate::Device for super::Device {
                 && self.shared.private_caps.supports_memoryless_storage
             {
                 MTLStorageMode::Memoryless
+            } else if cfg!(target_pointer_width = "32") {
+                // On arm64_32 (watchOS ILP32), the AGXMetalS4 driver (A13/S6 GPU)
+                // crashes in copyFromTexture:toBuffer: on Private textures — null
+                // deref at offset 0x50 in the driver's internal texture state. Use
+                // Shared storage which works correctly on Apple's unified memory
+                // architecture and matches what native Swift Metal code uses on
+                // these devices.
+                MTLStorageMode::Shared
             } else {
                 MTLStorageMode::Private
             };
@@ -1272,8 +1280,11 @@ impl crate::Device for super::Device {
             }
 
             // https://developer.apple.com/documentation/metal/mtlpipelinebufferdescriptor/mutability
-            let supports_mutability =
-                available!(macos = 10.13, ios = 11.0, tvos = 11.0, visionos = 1.0);
+            // Disabled on arm64_32 (watchOS ILP32): the AGXMetalS4 driver exhibits
+            // instability when mutability hints are combined with Shared storage
+            // mode textures. Conservative disable until broader device coverage.
+            let supports_mutability = !cfg!(target_pointer_width = "32")
+                && available!(macos = 10.13, ios = 11.0, tvos = 11.0, visionos = 1.0);
 
             let (primitive_class, raw_primitive_type) =
                 conv::map_primitive_topology(desc.primitive.topology);
diff --git a/wgpu-hal/src/metal/surface.rs b/wgpu-hal/src/metal/surface.rs
index e08ac591e6e..1b08c53d4e5 100644
--- a/wgpu-hal/src/metal/surface.rs
+++ b/wgpu-hal/src/metal/surface.rs
@@ -76,7 +76,8 @@ impl crate::Surface for super::Surface {
             wgt::PresentMode::Immediate => false,
             m => unreachable!("Unsupported present mode: {m:?}"),
         };
-        let drawable_size = CGSize::new(config.extent.width as f64, config.extent.height as f64);
+        // CGFloat is f64 on 64-bit, f32 on 32-bit (arm64_32/ILP32)
+        let drawable_size = CGSize::new(config.extent.width as _, config.extent.height as _);
 
         match config.composite_alpha_mode {
             wgt::CompositeAlphaMode::Opaque => render_layer.setOpaque(true),