diff --git a/core/src/apps/thp/pairing.py b/core/src/apps/thp/pairing.py
index a14e4d032e..0f47e6b967 100644
--- a/core/src/apps/thp/pairing.py
+++ b/core/src/apps/thp/pairing.py
@@ -129,7 +129,7 @@ async def _prepare_pairing(ctx: PairingContext) -> None:
 async def show_display_data(
     ctx: PairingContext, expected_types: Container[int] = ()
 ) -> type[protobuf.MessageType]:
-    from trezorui2 import CANCELLED
+    from trezorui_api import CANCELLED
 
     read_task = ctx.read(expected_types)
     cancel_task = ctx.display_data.get_display_layout()
diff --git a/core/src/trezor/wire/thp/channel.py b/core/src/trezor/wire/thp/channel.py
index 2e6b78ef89..e085163b2c 100644
--- a/core/src/trezor/wire/thp/channel.py
+++ b/core/src/trezor/wire/thp/channel.py
@@ -132,7 +132,7 @@ class Channel:
                 # TODO Check CRC and if valid, check tag, if valid update nonces
                 self._finish_fallback()
                 # TODO self.write() failure device is busy - use channel buffer to send this failure message!!
-                return
+                return None
             return received_message_handler.handle_received_message(self, buffer)
         elif self.expected_payload_length + INIT_HEADER_LENGTH > self.bytes_read:
             self.is_cont_packet_expected = True
diff --git a/core/src/trezor/wire/thp/pairing_context.py b/core/src/trezor/wire/thp/pairing_context.py
index 34065b122f..02f8db3a8a 100644
--- a/core/src/trezor/wire/thp/pairing_context.py
+++ b/core/src/trezor/wire/thp/pairing_context.py
@@ -1,7 +1,7 @@
 from typing import TYPE_CHECKING
 from ubinascii import hexlify
 
-import trezorui2
+import trezorui_api
 from trezor import loop, protobuf, workflow
 from trezor.crypto import random
 from trezor.wire import context, message_handler, protocol_common
@@ -42,7 +42,7 @@ class PairingDisplayData:
             code_str = self._get_code_code_entry_str()
 
         return ui.Layout(
-            trezorui2.show_address_details(  # noqa
+            trezorui_api.show_address_details(  # noqa
                 qr_title="Scan QR code to pair",
                 address=qr_str,
                 case_sensitive=True,
diff --git a/core/tests/test_apps.bitcoin.approver.py b/core/tests/test_apps.bitcoin.approver.py
index 17a870df7f..408f96d7ee 100644
--- a/core/tests/test_apps.bitcoin.approver.py
+++ b/core/tests/test_apps.bitcoin.approver.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 
 import storage.cache_codec
@@ -12,13 +13,13 @@ from trezor.messages import (
     TxOutput,
 )
 from trezor.wire import context
+from trezor.wire.codec.codec_context import CodecContext
 
 from apps.bitcoin.authorization import FEE_RATE_DECIMALS, CoinJoinAuthorization
 from apps.bitcoin.sign_tx.approvers import CoinJoinApprover
 from apps.bitcoin.sign_tx.bitcoin import Bitcoin
 from apps.bitcoin.sign_tx.tx_info import TxInfo
 from apps.common import coins
-from trezor.wire.codec.codec_context import CodecContext
 
 if utils.USE_THP:
     import thp_common
diff --git a/core/tests/test_apps.bitcoin.authorization.py b/core/tests/test_apps.bitcoin.authorization.py
index 4faf202989..aedcadba92 100644
--- a/core/tests/test_apps.bitcoin.authorization.py
+++ b/core/tests/test_apps.bitcoin.authorization.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 
 import storage.cache_codec
diff --git a/core/tests/test_storage.cache.py b/core/tests/test_storage.cache.py
index 8b426dd070..1e43e09d98 100644
--- a/core/tests/test_storage.cache.py
+++ b/core/tests/test_storage.cache.py
@@ -14,10 +14,11 @@ if utils.USE_THP:
     _PROTOCOL_CACHE = cache_thp
 
 else:
+    from mock_storage import mock_storage
     from storage import cache, cache_codec
     from trezor.messages import EndSession, Initialize
+
     from apps.base import handle_EndSession
-    from mock_storage import mock_storage
 
     _PROTOCOL_CACHE = cache_codec
 
@@ -319,8 +320,8 @@ class TestStorageCache(unittest.TestCase):
     else:
 
         def setUpClass(self):
-            from trezor.wire.codec.codec_context import CodecContext
             from trezor.wire import context
+            from trezor.wire.codec.codec_context import CodecContext
 
             context.CURRENT_CONTEXT = CodecContext(None, bytearray(64))
 
@@ -377,7 +378,7 @@ class TestStorageCache(unittest.TestCase):
             session_id = cache_codec.start_session()
             self.assertEqual(cache_codec.start_session(session_id), session_id)
             get_active_session().set(KEY, b"A")
-            for i in range(_PROTOCOL_CACHE._MAX_SESSIONS_COUNT):
+            for _ in range(_PROTOCOL_CACHE._MAX_SESSIONS_COUNT):
                 cache_codec.start_session()
             self.assertNotEqual(cache_codec.start_session(session_id), session_id)
             self.assertIsNone(get_active_session().get(KEY))
diff --git a/core/tests/test_trezor.wire.thp.checksum.py b/core/tests/test_trezor.wire.thp.checksum.py
index 41c9325001..f5d59d6805 100644
--- a/core/tests/test_trezor.wire.thp.checksum.py
+++ b/core/tests/test_trezor.wire.thp.checksum.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 
 if utils.USE_THP:
diff --git a/core/tests/test_trezor.wire.thp.crypto.py b/core/tests/test_trezor.wire.thp.crypto.py
index d26785ce65..1eee57f8cb 100644
--- a/core/tests/test_trezor.wire.thp.crypto.py
+++ b/core/tests/test_trezor.wire.thp.crypto.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 from trezorcrypto import aesgcm, curve25519
 
@@ -101,8 +102,8 @@ class TestTrezorHostProtocolCrypto(unittest.TestCase):
 
     def test_iv_from_nonce(self):
         for v in self.vectors_iv:
-            x = v[0]
-            y = x.to_bytes(8, "big")
+            # x = v[0]
+            # y = x.to_bytes(8, "big")
             iv = crypto._get_iv_from_nonce(v[0])
             self.assertEqual(iv, v[1])
         with self.assertRaises(AssertionError) as e:
diff --git a/core/tests/test_trezor.wire.thp.py b/core/tests/test_trezor.wire.thp.py
index 95f6cb6322..f4e0bce287 100644
--- a/core/tests/test_trezor.wire.thp.py
+++ b/core/tests/test_trezor.wire.thp.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 from mock_wire_interface import MockHID
 from trezor import config, io, protobuf
@@ -28,8 +29,13 @@ if utils.USE_THP:
         ThpEndRequest,
         ThpStartPairingRequest,
     )
-    from trezor.wire.thp import thp_main, memory_manager
-    from trezor.wire.thp import ChannelState, checksum, interface_manager
+    from trezor.wire.thp import (
+        ChannelState,
+        checksum,
+        interface_manager,
+        memory_manager,
+        thp_main,
+    )
     from trezor.wire.thp.crypto import Handshake
     from trezor.wire.thp.pairing_context import PairingContext
 
@@ -251,7 +257,7 @@ class TestTrezorHostProtocol(unittest.TestCase):
 
         # test invalid tag in handshake phase
         cid_2 = get_channel_id_from_response(expected_response_1)
-        cid_2_bytes = cid_2.to_bytes(2, "big")
+        # cid_2_bytes = cid_2.to_bytes(2, "big")
         channel = thp_main._CHANNELS[cid_2]
         channel.iface = self.interface
 
diff --git a/core/tests/test_trezor.wire.thp.writer.py b/core/tests/test_trezor.wire.thp.writer.py
index 0e50f5c4b5..0f6110761a 100644
--- a/core/tests/test_trezor.wire.thp.writer.py
+++ b/core/tests/test_trezor.wire.thp.writer.py
@@ -1,13 +1,12 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 
 from typing import Any, Awaitable
 
-
 if utils.USE_THP:
     import thp_common
     from mock_wire_interface import MockHID
-    from trezor.wire.thp import writer
-    from trezor.wire.thp import ENCRYPTED, PacketHeader
+    from trezor.wire.thp import ENCRYPTED, PacketHeader, writer
 
 
 @unittest.skipUnless(utils.USE_THP, "only needed for THP")
diff --git a/core/tests/test_trezor.wire.thp_deprecated.py b/core/tests/test_trezor.wire.thp_deprecated.py
index 12ef40bb7e..49f2256e69 100644
--- a/core/tests/test_trezor.wire.thp_deprecated.py
+++ b/core/tests/test_trezor.wire.thp_deprecated.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from common import *  # isort:skip
 import ustruct
 from typing import TYPE_CHECKING
@@ -11,9 +12,8 @@ from trezor.wire.protocol_common import Message
 if utils.USE_THP:
     import thp_common
     import trezor.wire.thp
-    from trezor.wire.thp import thp_main
     from trezor.wire.thp import alternating_bit_protocol as ABP
-    from trezor.wire.thp import checksum
+    from trezor.wire.thp import checksum, thp_main
     from trezor.wire.thp.checksum import CHECKSUM_LENGTH
     from trezor.wire.thp.writer import PACKET_LENGTH
 
diff --git a/core/tests/thp_common.py b/core/tests/thp_common.py
index d22243d29e..86a023d3c6 100644
--- a/core/tests/thp_common.py
+++ b/core/tests/thp_common.py
@@ -1,3 +1,4 @@
+# flake8: noqa: F403,F405
 from trezor import utils
 from trezor.wire.thp import ChannelState