diff --git a/python/src/trezorlib/client.py b/python/src/trezorlib/client.py
index fb888b404..a75be139a 100644
--- a/python/src/trezorlib/client.py
+++ b/python/src/trezorlib/client.py
@@ -297,7 +297,7 @@ class TrezorClient:
         if not isinstance(resp, messages.Features):
             raise exceptions.TrezorException("Unexpected response to Initialize")
 
-        if resp.session_id == self.session_id:
+        if self.session_id is not None and resp.session_id == self.session_id:
             LOG.info("Successfully resumed session")
         elif session_id is not None:
             LOG.info("Failed to resume session")