diff --git a/core/src/apps/debug/__init__.py b/core/src/apps/debug/__init__.py
index 42f2ae05b..8673210fc 100644
--- a/core/src/apps/debug/__init__.py
+++ b/core/src/apps/debug/__init__.py
@@ -61,7 +61,7 @@ if __debug__:
 
     loop.schedule(debuglink_decision_dispatcher())
 
-    async def return_layout_change(ctx: wire.Context):
+    async def return_layout_change(ctx: wire.Context) -> None:
         content = await layout_change_chan.take()
         await ctx.write(DebugLinkLayout(lines=content))
 
diff --git a/core/src/apps/management/recovery_device/layout.py b/core/src/apps/management/recovery_device/layout.py
index fb216dbc9..9c9aceddd 100644
--- a/core/src/apps/management/recovery_device/layout.py
+++ b/core/src/apps/management/recovery_device/layout.py
@@ -312,7 +312,7 @@ class RecoveryHomescreen(ui.Component):
 
     if __debug__:
 
-        def read_content(self):
+        def read_content(self) -> List[str]:
             return [self.__class__.__name__, self.text, self.subtext or ""]
 
 
diff --git a/core/src/trezor/ui/__init__.py b/core/src/trezor/ui/__init__.py
index 68f680f72..e6b1ae990 100644
--- a/core/src/trezor/ui/__init__.py
+++ b/core/src/trezor/ui/__init__.py
@@ -9,7 +9,7 @@ if __debug__:
     from apps.debug import notify_layout_change
 
 if False:
-    from typing import Any, Awaitable, Generator, Tuple, TypeVar
+    from typing import Any, Awaitable, Generator, List, Tuple, TypeVar
 
     Pos = Tuple[int, int]
     Area = Tuple[int, int, int, int]
diff --git a/core/src/trezor/ui/button.py b/core/src/trezor/ui/button.py
index 014866573..9195f60a5 100644
--- a/core/src/trezor/ui/button.py
+++ b/core/src/trezor/ui/button.py
@@ -4,7 +4,7 @@ from trezor import ui
 from trezor.ui import display, in_area
 
 if False:
-    from typing import List, Type, Union
+    from typing import List, Optional, Type, Union
 
 
 class ButtonDefault: