diff --git a/python/src/trezorlib/debuglink.py b/python/src/trezorlib/debuglink.py
index 2bffb86efe..dbf416f244 100644
--- a/python/src/trezorlib/debuglink.py
+++ b/python/src/trezorlib/debuglink.py
@@ -1036,7 +1036,7 @@ class SessionDebugWrapper(Session):
         elif isinstance(session, SessionDebugWrapper):
             raise Exception("Cannot wrap already wrapped session!")
         else:
-            self.session_version = -1  # UNKNOWN
+            self.client.session_version = -1  # UNKNOWN
 
     @property
     def session_version(self) -> int:
diff --git a/tests/persistence_tests/test_shamir_persistence.py b/tests/persistence_tests/test_shamir_persistence.py
index c8707aeb82..a545ee556c 100644
--- a/tests/persistence_tests/test_shamir_persistence.py
+++ b/tests/persistence_tests/test_shamir_persistence.py
@@ -16,12 +16,10 @@
 
 import pytest
 
-from trezorlib import device
-from trezorlib import messages
-from trezorlib.debuglink import DebugLink, LayoutType, SessionDebugWrapper as Session
-from trezorlib.messages import RecoveryStatus, WipeDevice
-
-from tests import buttons
+from trezorlib import device, messages
+from trezorlib.debuglink import DebugLink, LayoutType
+from trezorlib.debuglink import SessionDebugWrapper as Session
+from trezorlib.messages import RecoveryStatus
 
 from ..click_tests import common, recovery
 from ..common import MNEMONIC_SLIP39_ADVANCED_20, MNEMONIC_SLIP39_BASIC_20_3of6
diff --git a/tests/upgrade_tests/test_firmware_upgrades.py b/tests/upgrade_tests/test_firmware_upgrades.py
index 4cf7e085fe..dd0180be3d 100644
--- a/tests/upgrade_tests/test_firmware_upgrades.py
+++ b/tests/upgrade_tests/test_firmware_upgrades.py
@@ -20,8 +20,7 @@ from typing import TYPE_CHECKING, List, Optional
 import pytest
 from shamir_mnemonic import shamir
 
-from trezorlib import btc, debuglink, device, exceptions, fido, models
-from trezorlib import messages
+from trezorlib import btc, debuglink, device, exceptions, fido, messages, models
 from trezorlib.debuglink import SessionDebugWrapper as Session
 from trezorlib.messages import (
     ApplySettings,