diff --git a/core/src/trezor/wire/protocol_common.py b/core/src/trezor/wire/protocol_common.py
index 93b77e617..8d091d8e5 100644
--- a/core/src/trezor/wire/protocol_common.py
+++ b/core/src/trezor/wire/protocol_common.py
@@ -2,19 +2,30 @@ from trezor import protobuf
 
 
 class Message:
+    def __init__(
+        self,
+        message_data: bytes,
+    ) -> None:
+        self.data = message_data
+
+    def to_bytes(self):
+        return self.data
+
+
+class MessageWithType(Message):
     def __init__(
         self,
         message_type: int,
         message_data: bytes,
     ) -> None:
         self.type = message_type
-        self.data = message_data
+        super().__init__(message_data)
 
     def to_bytes(self):
         return self.type.to_bytes(2, "big") + self.data
 
 
-class MessageWithId(Message):
+class MessageWithId(MessageWithType):
     def __init__(
         self,
         message_type: int,
diff --git a/core/src/trezor/wire/thp/thp_messages.py b/core/src/trezor/wire/thp/thp_messages.py
index 12b4649dd..1bcd87382 100644
--- a/core/src/trezor/wire/thp/thp_messages.py
+++ b/core/src/trezor/wire/thp/thp_messages.py
@@ -60,7 +60,7 @@ _ERROR_UNALLOCATED_SESSION = (
 
 
 def get_device_properties() -> Message:
-    return Message(1000, _ENCODED_PROTOBUF_DEVICE_PROPERTIES)
+    return Message(_ENCODED_PROTOBUF_DEVICE_PROPERTIES)
 
 
 def get_channel_allocation_response(nonce: bytes, new_cid: int) -> bytes: