diff --git a/python/src/trezorlib/transport/session.py b/python/src/trezorlib/transport/session.py
index 1aae80eb9e..5ad859eec4 100644
--- a/python/src/trezorlib/transport/session.py
+++ b/python/src/trezorlib/transport/session.py
@@ -97,6 +97,7 @@ class SessionV1(Session):
             session = SessionV1(client, session_id)
         session.button_callback = client.button_callback
         session.pin_callback = client.pin_callback
+        session._init_session(derive_cardano=derive_cardano)
         return session
 
     def _write(self, msg: t.Any) -> None:
@@ -109,6 +110,12 @@ class SessionV1(Session):
             assert isinstance(self.client.protocol, ProtocolV1)
         return self.client.protocol.read()
 
+    def _init_session(self, derive_cardano: bool = False):
+        self._write(
+            messages.Initialize(session_id=self.id, derive_cardano=derive_cardano)
+        )
+        _ = self._read()
+
 
 def _callback_button(session: Session, msg: t.Any) -> t.Any:
     print("Please confirm action on your Trezor device.")  # TODO how to handle UI?