diff --git a/components/script/dom/bluetoothremotegattcharacteristic.rs b/components/script/dom/bluetoothremotegattcharacteristic.rs
index 390878342dbc..2cb039959f3c 100644
--- a/components/script/dom/bluetoothremotegattcharacteristic.rs
+++ b/components/script/dom/bluetoothremotegattcharacteristic.rs
@@ -300,9 +300,8 @@ impl AsyncBluetoothListener for BluetoothRemoteGATTCharacteristic {
                 promise.resolve_native(promise_cx, &value);
             },
             BluetoothResponse::WriteValue(result) => {
-                let value = ByteString::new(result);
-                *self.value.borrow_mut() = Some(value.clone());
-                promise.resolve_native(promise_cx, &value);
+                *self.value.borrow_mut() = Some(ByteString::new(result));
+                promise.resolve_native(promise_cx, &());
             },
             BluetoothResponse::EnableNotification(_result) => {
                 promise.resolve_native(promise_cx, self);
diff --git a/components/script/dom/bluetoothremotegattdescriptor.rs b/components/script/dom/bluetoothremotegattdescriptor.rs
index ffe66c23becc..c5b67a44aec9 100644
--- a/components/script/dom/bluetoothremotegattdescriptor.rs
+++ b/components/script/dom/bluetoothremotegattdescriptor.rs
@@ -137,9 +137,8 @@ impl AsyncBluetoothListener for BluetoothRemoteGATTDescriptor {
                 promise.resolve_native(promise_cx, &value);
             },
             BluetoothResponse::WriteValue(result) => {
-                let value = ByteString::new(result);
-                *self.value.borrow_mut() = Some(value.clone());
-                promise.resolve_native(promise_cx, &value);
+                *self.value.borrow_mut() = Some(ByteString::new(result));
+                promise.resolve_native(promise_cx, &());
             },
             _ => promise.reject_error(promise_cx, Error::Type("Something went wrong...".to_owned())),
         }
diff --git a/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/characteristic/write-succeeds.html b/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/characteristic/write-succeeds.html
index f87d4c9d8ce6..4db85c7164f2 100644
--- a/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/characteristic/write-succeeds.html
+++ b/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/characteristic/write-succeeds.html
@@ -13,6 +13,7 @@
     .then(device => device.gatt.connect())
     .then(gattServer => gattServer.getPrimaryService(generic_access.name))
     .then(service => service.getCharacteristic(device_name.name))
-    .then(characteristic => characteristic.writeValue(new Uint8Array(1)));
+    .then(characteristic => characteristic.writeValue(new Uint8Array(1)))
+    .then(result => assert_equals(result, undefined));
 }, 'A regular write request to a writable characteristic should succeed.');
 </script>
diff --git a/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/descriptor/write-succeeds.html b/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/descriptor/write-succeeds.html
index 61afdd2a2dc8..bb72220fe04b 100644
--- a/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/descriptor/write-succeeds.html
+++ b/tests/wpt/mozilla/tests/mozilla/bluetooth/writeValue/descriptor/write-succeeds.html
@@ -14,6 +14,7 @@
     .then(gattServer => gattServer.getPrimaryService(generic_access.name))
     .then(service => service.getCharacteristic(device_name.name))
     .then(characteristic => characteristic.getDescriptor(number_of_digitals.name))
-    .then(descriptor => descriptor.writeValue(new Uint8Array(1)));
+    .then(descriptor => descriptor.writeValue(new Uint8Array(1)))
+    .then(result => assert_equals(result, undefined));
 }, 'A regular write request to a writable descriptor should succeed.');
 </script>