feat(core): implement micropython app_loader/cache wrapper

diff --git a/core/SConscript.firmware b/core/SConscript.firmware
index f8f0d6c1..386d7aa3 100644
--- a/core/SConscript.firmware
+++ b/core/SConscript.firmware
@@ -281,7 +281,11 @@ if not PRODUCTION:
     SOURCE_MOD += ['embed/rtl/printf.c']
 
 if "app_loading" in FEATURES_WANTED:
-    SOURCE_MOD += ['embed/api/trezor_api_v1_impl.c']
+    SOURCE_MOD += [
+        'embed/api/trezor_api_v1_impl.c',
+        'embed/upymod/modtrezorapp/modtrezorapp.c',
+    ]
+
 
 CPPDEFINES_MOD += [
     'TRANSLATIONS',
diff --git a/core/SConscript.unix b/core/SConscript.unix
index 28964f1c..3141a47c 100644
--- a/core/SConscript.unix
+++ b/core/SConscript.unix
@@ -430,7 +430,10 @@ SOURCE_UNIX = [
 ]
 
 if "app_loading" in FEATURES_WANTED:
-    SOURCE_UNIX += ['embed/api/trezor_api_v1_impl.c']
+    SOURCE_UNIX += [
+        'embed/api/trezor_api_v1_impl.c',
+        'embed/upymod/modtrezorapp/modtrezorapp.c',
+    ]
 
 
 TRANSLATION_DATA = [
diff --git a/core/embed/projects/firmware/mpconfigport.h b/core/embed/projects/firmware/mpconfigport.h
index 55463904..7d38157a 100644
--- a/core/embed/projects/firmware/mpconfigport.h
+++ b/core/embed/projects/firmware/mpconfigport.h
@@ -172,6 +172,7 @@
 #define MICROPY_PY_TREZORPROTO      (1)
 #define MICROPY_PY_TREZORTRANSLATE  (1)
 #define MICROPY_PY_TREZORUI_API     (1)
+#define MICROPY_PY_TREZORAPP        (USE_APP_LOADING)
 
 #define MP_STATE_PORT MP_STATE_VM
 
diff --git a/core/embed/projects/unix/mpconfigport.h b/core/embed/projects/unix/mpconfigport.h
index 0485f1b7..70a8beb0 100644
--- a/core/embed/projects/unix/mpconfigport.h
+++ b/core/embed/projects/unix/mpconfigport.h
@@ -221,6 +221,7 @@ extern const struct _mp_print_t mp_stderr_print;
 #define MICROPY_PY_TREZORPROTO      (1)
 #define MICROPY_PY_TREZORTRANSLATE  (1)
 #define MICROPY_PY_TREZORUI_API     (1)
+#define MICROPY_PY_TREZORAPP        (USE_APP_LOADING)
 
 #define MP_STATE_PORT MP_STATE_VM
 
diff --git a/core/embed/upymod/modtrezorapp/modtrezorapp-image.h b/core/embed/upymod/modtrezorapp/modtrezorapp-image.h
new file mode 100644
index 00000000..1bef6d19
--- /dev/null
+++ b/core/embed/upymod/modtrezorapp/modtrezorapp-image.h
@@ -0,0 +1,91 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <trezor_rtl.h>
+
+#include <io/app_loader.h>
+
+/// package: trezorapp.__init__
+
+/// class AppImage:
+///     """
+///     Application image image.
+///     """
+typedef struct _mp_obj_AppImage_t {
+  mp_obj_base_t base;
+  app_cache_handle_t image;
+} mp_obj_AppImage_t;
+
+/// def write(self, offset: int, data: AnyBytes) -> None
+///     """
+///     Writes data to the application image at the specified offset.
+///     """
+STATIC mp_obj_t mod_trezorapp_AppImage_write(mp_obj_t self, mp_obj_t offset_obj,
+                                             mp_obj_t data_obj) {
+  mp_obj_AppImage_t *o = MP_OBJ_TO_PTR(self);
+  app_cache_handle_t image = o->image;
+
+  mp_buffer_info_t bufinfo = {0};
+  mp_get_buffer_raise(data_obj, &bufinfo, MP_BUFFER_READ);
+
+  uintptr_t offset = mp_obj_get_int(offset_obj);
+
+  if (!app_cache_write_image(image, offset, bufinfo.buf, bufinfo.len)) {
+    mp_raise_msg(&mp_type_RuntimeError,
+                 MP_ERROR_TEXT("Failed to write to app image."));
+  }
+
+  return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorapp_AppImage_write_obj,
+                                 mod_trezorapp_AppImage_write);
+
+/// def finalize(self, bool accept) -> None:
+///     """
+/// Finalizes loading of the application image. If `accept` is true,
+/// the image is marked as loaded and will be available for execution.
+/// If `accept` is false, the image is discarded.
+///     """
+STATIC mp_obj_t mod_trezorapp_AppImage_finalize(mp_obj_t self,
+                                                mp_obj_t accept_obj) {
+  mp_obj_AppImage_t *o = MP_OBJ_TO_PTR(self);
+
+  bool accept = mp_obj_is_true(accept_obj);
+
+  app_cache_finalize_image(o->image, accept);
+  o->image = APP_CACHE_INVALID_HANDLE;
+
+  return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorapp_AppImage_finalize_obj,
+                                 mod_trezorapp_AppImage_finalize);
+
+STATIC const mp_rom_map_elem_t mod_trezorapp_AppImage_locals_dict_table[] = {
+    {MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mod_trezorapp_AppImage_write_obj)},
+    {MP_ROM_QSTR(MP_QSTR_finalize),
+     MP_ROM_PTR(&mod_trezorapp_AppImage_finalize_obj)},
+};
+STATIC MP_DEFINE_CONST_DICT(mod_trezorapp_AppImage_locals_dict,
+                            mod_trezorapp_AppImage_locals_dict_table);
+
+STATIC const mp_obj_type_t mod_trezorapp_AppImage_type = {
+    {&mp_type_type},
+    .name = MP_QSTR_AppImage,
+    .locals_dict = (void *)&mod_trezorapp_AppImage_locals_dict,
+};
diff --git a/core/embed/upymod/modtrezorapp/modtrezorapp-task.h b/core/embed/upymod/modtrezorapp/modtrezorapp-task.h
new file mode 100644
index 00000000..ddfd4179
--- /dev/null
+++ b/core/embed/upymod/modtrezorapp/modtrezorapp-task.h
@@ -0,0 +1,91 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <trezor_rtl.h>
+
+#include <io/app_loader.h>
+
+/// package: trezorapp.__init__
+
+/// class AppTask:
+///     """
+///     App task structure.
+///     """
+typedef struct _mp_obj_AppTask_t {
+  mp_obj_base_t base;
+  systask_id_t task_id;
+} mp_obj_AppTask_t;
+
+/// def id(self) -> int:
+///     """
+///     Returns the task id.
+///     """
+STATIC mp_obj_t mod_trezorapp_AppTask_id(mp_obj_t self) {
+  mp_obj_AppTask_t *o = MP_OBJ_TO_PTR(self);
+  return MP_OBJ_NEW_SMALL_INT(o->task_id);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorapp_AppTask_id_obj,
+                                 mod_trezorapp_AppTask_id);
+
+/// def is_running(self) -> bool:
+///     """
+///     Returns whether the application is still running.
+///     """
+STATIC mp_obj_t mod_trezorapp_AppTask_is_running(mp_obj_t self) {
+  mp_obj_AppTask_t *o = MP_OBJ_TO_PTR(self);
+
+  if (app_task_is_running(o->task_id)) {
+    return mp_const_true;
+  } else {
+    return mp_const_false;
+  }
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorapp_AppTask_is_running_obj,
+                                 mod_trezorapp_AppTask_is_running);
+
+/// def unload(self) -> None:
+///     """
+///     Unloads the application associated with this task.
+///     """
+STATIC mp_obj_t mod_trezorapp_AppTask_unload(mp_obj_t self) {
+  mp_obj_AppTask_t *o = MP_OBJ_TO_PTR(self);
+
+  app_task_unload(o->task_id);
+  o->task_id = 0;
+
+  return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorapp_AppTask_unload_obj,
+                                 mod_trezorapp_AppTask_unload);
+
+STATIC const mp_rom_map_elem_t mod_trezorapp_AppTask_locals_dict_table[] = {
+    {MP_ROM_QSTR(MP_QSTR_id), MP_ROM_PTR(&mod_trezorapp_AppTask_id_obj)},
+    {MP_ROM_QSTR(MP_QSTR_is_running),
+     MP_ROM_PTR(&mod_trezorapp_AppTask_is_running_obj)},
+    {MP_ROM_QSTR(MP_QSTR_unload),
+     MP_ROM_PTR(&mod_trezorapp_AppTask_unload_obj)},
+};
+STATIC MP_DEFINE_CONST_DICT(mod_trezorapp_AppTask_locals_dict,
+                            mod_trezorapp_AppTask_locals_dict_table);
+
+STATIC const mp_obj_type_t mod_trezorapp_AppTask_type = {
+    {&mp_type_type},
+    .name = MP_QSTR_AppTask,
+    .locals_dict = (void *)&mod_trezorapp_AppTask_locals_dict,
+};
diff --git a/core/embed/upymod/modtrezorapp/modtrezorapp.c b/core/embed/upymod/modtrezorapp/modtrezorapp.c
new file mode 100644
index 00000000..f82a7169
--- /dev/null
+++ b/core/embed/upymod/modtrezorapp/modtrezorapp.c
@@ -0,0 +1,150 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <trezor_rtl.h>
+
+#include <unistd.h>
+
+#include "py/mphal.h"
+#include "py/objstr.h"
+#include "py/runtime.h"
+
+#if MICROPY_PY_TREZORAPP
+
+#include <io/app_cache.h>
+#include <io/app_loader.h>
+
+#include "embed/upymod/trezorobj.h"
+
+#include "modtrezorapp-image.h"
+#include "modtrezorapp-task.h"
+
+/// package: trezorapp.__init__
+
+/// def spawn_task(app_hash: bytes) -> AppTask:
+///     """
+///     Spawns an application task from the app cache.
+///     """
+STATIC mp_obj_t mod_trezorapp_spawn_task(mp_obj_t app_hash_obj) {
+  mp_buffer_info_t hash = {0};
+  mp_get_buffer_raise(app_hash_obj, &hash, MP_BUFFER_READ);
+
+  if (hash.len != sizeof(app_hash_t)) {
+    mp_raise_ValueError(MP_ERROR_TEXT("Invalid app hash size"));
+  }
+
+  const app_hash_t *hash_ptr = (const app_hash_t *)hash.buf;
+
+  systask_id_t task_id;
+  if (!app_task_spawn(hash_ptr, &task_id)) {
+    mp_raise_msg(&mp_type_RuntimeError,
+                 MP_ERROR_TEXT("Failed to spawn app from app cache"));
+  }
+
+  mp_obj_AppTask_t *o =
+      mp_obj_malloc(mp_obj_AppTask_t, &mod_trezorapp_AppTask_type);
+  o->task_id = task_id;
+  return MP_OBJ_FROM_PTR(o);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorapp_spawn_task_obj,
+                                 mod_trezorapp_spawn_task);
+
+/// def create_image(app_hash: bytes, size: int) -> AppImage:
+///     """
+///     Creates a new application image in the app cache.
+///     """
+STATIC mp_obj_t mod_trezorapp_create_image(mp_obj_t app_hash_obj,
+                                           mp_obj_t size_obj) {
+  mp_buffer_info_t hash = {0};
+  mp_get_buffer_raise(app_hash_obj, &hash, MP_BUFFER_READ);
+
+  if (hash.len != sizeof(app_hash_t)) {
+    mp_raise_ValueError(MP_ERROR_TEXT("Invalid app hash size"));
+  }
+
+  const app_hash_t *hash_ptr = (const app_hash_t *)hash.buf;
+
+  size_t size = mp_obj_get_int(size_obj);
+
+  app_cache_handle_t image = app_cache_create_image(hash_ptr, size);
+
+  if (image == APP_CACHE_INVALID_HANDLE) {
+    mp_raise_msg(&mp_type_RuntimeError,
+                 MP_ERROR_TEXT("Failed to create app image in app cache"));
+  }
+  mp_obj_AppImage_t *o =
+      mp_obj_malloc(mp_obj_AppImage_t, &mod_trezorapp_AppImage_type);
+  o->image = image;
+  return MP_OBJ_FROM_PTR(o);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorapp_create_image_obj,
+                                 mod_trezorapp_create_image);
+
+#ifdef TREZOR_EMULATOR
+/// def load_file(app_hash: bytes, filename: Str) -> None:
+///     """
+///     Loads an application image from a file into the app cache.
+///     """
+STATIC mp_obj_t mod_trezorapp_load_file(mp_obj_t app_hash_obj,
+                                        mp_obj_t filename_obj) {
+  mp_buffer_info_t hash = {0};
+  mp_get_buffer_raise(app_hash_obj, &hash, MP_BUFFER_READ);
+
+  if (hash.len != sizeof(app_hash_t)) {
+    mp_raise_ValueError(MP_ERROR_TEXT("Invalid app hash size"));
+  }
+
+  const app_hash_t *hash_ptr = (const app_hash_t *)hash.buf;
+
+  const char *filename = mp_obj_str_get_str(filename_obj);
+
+  if (!app_cache_load_file(hash_ptr, filename)) {
+    mp_raise_msg(&mp_type_RuntimeError,
+                 MP_ERROR_TEXT("Failed to load app image from file"));
+  }
+
+  return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorapp_load_file_obj,
+                                 mod_trezorapp_load_file);
+#endif  // TREZOR_EMULATOR
+
+STATIC const mp_rom_map_elem_t mp_module_trezorapp_globals_table[] = {
+    {MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_trezorapp)},
+
+    {MP_ROM_QSTR(MP_QSTR_spawn_task),
+     MP_ROM_PTR(&mod_trezorapp_spawn_task_obj)},
+    {MP_ROM_QSTR(MP_QSTR_create_image),
+     MP_ROM_PTR(&mod_trezorapp_create_image_obj)},
+#ifdef TREZOR_EMULATOR
+    {MP_ROM_QSTR(MP_QSTR_load_file), MP_ROM_PTR(&mod_trezorapp_load_file_obj)},
+#endif
+};
+
+STATIC MP_DEFINE_CONST_DICT(mp_module_trezorapp_globals,
+                            mp_module_trezorapp_globals_table);
+
+const mp_obj_module_t mp_module_trezorapp = {
+    .base = {&mp_type_module},
+    .globals = (mp_obj_dict_t *)&mp_module_trezorapp_globals,
+};
+
+MP_REGISTER_MODULE(MP_QSTR_trezorapp, mp_module_trezorapp);
+
+#endif  // MICROPY_PY_TREZORAPP
diff --git a/core/embed/upymod/modtrezorio/modtrezorio.c b/core/embed/upymod/modtrezorio/modtrezorio.c
index 3260c2cf..1bea4688 100644
--- a/core/embed/upymod/modtrezorio/modtrezorio.c
+++ b/core/embed/upymod/modtrezorio/modtrezorio.c
@@ -70,7 +70,7 @@ uint32_t last_touch_sample_time = 0;
 #include "modtrezorio-poll.h"
 
 /// package: trezorio.__init__
-/// from . import fatfs, haptic, sdcard, ble, pm, rgb_led, ipc
+/// from . import fatfs, haptic, sdcard, ble, pm, rgb_led, ipc, app_cache
 
 /// POLL_READ: int  # wait until interface is readable and return read data
 /// POLL_WRITE: int  # wait until interface is writable
@@ -140,7 +140,6 @@ STATIC const mp_rom_map_elem_t mp_module_trezorio_globals_table[] = {
     {MP_ROM_QSTR(MP_QSTR_IPC2_EVENT), MP_ROM_INT(SYSHANDLE_IPC2)},
     {MP_ROM_QSTR(MP_QSTR_ipc_send), MP_ROM_PTR(&mod_trezorio_ipc_send_obj)},
 #endif
-
     {MP_ROM_QSTR(MP_QSTR_USB), MP_ROM_PTR(&mod_trezorio_USB_type)},
     {MP_ROM_QSTR(MP_QSTR_USBIF), MP_ROM_PTR(&mod_trezorio_USBIF_type)},
     {MP_ROM_QSTR(MP_QSTR_USBIF_WIRE), MP_ROM_INT(SYSHANDLE_USB_WIRE)},
diff --git a/core/embed/upymod/modtrezorutils/modtrezorutils.c b/core/embed/upymod/modtrezorutils/modtrezorutils.c
index 5f64a67c..44ac582b 100644
--- a/core/embed/upymod/modtrezorutils/modtrezorutils.c
+++ b/core/embed/upymod/modtrezorutils/modtrezorutils.c
@@ -761,6 +761,8 @@ STATIC const mp_obj_tuple_t mod_trezorutils_version_obj = {
 /// """Whether the hardware has a nRF chip."""
 /// USE_DBG_CONSOLE: bool
 /// """Whether a debug console is enabled."""
+/// USE_APP_LOADING: bool
+/// """Whether the firmware supports loading 3rd-party applications."""
 /// MODEL: str
 /// """Model name."""
 /// MODEL_FULL_NAME: str
@@ -952,6 +954,11 @@ STATIC const mp_rom_map_elem_t mp_module_trezorutils_globals_table[] = {
     {MP_ROM_QSTR(MP_QSTR_USE_DBG_CONSOLE), mp_const_true},
 #else
     {MP_ROM_QSTR(MP_QSTR_USE_DBG_CONSOLE), mp_const_false},
+#endif
+#ifdef USE_APP_LOADING
+    {MP_ROM_QSTR(MP_QSTR_USE_APP_LOADING), mp_const_true},
+#else
+    {MP_ROM_QSTR(MP_QSTR_USE_APP_LOADING), mp_const_false},
 #endif
     {MP_ROM_QSTR(MP_QSTR_MODEL), MP_ROM_PTR(&mod_trezorutils_model_name_obj)},
     {MP_ROM_QSTR(MP_QSTR_MODEL_FULL_NAME),
diff --git a/core/mocks/generated/trezorapp/__init__.pyi b/core/mocks/generated/trezorapp/__init__.pyi
new file mode 100644
index 00000000..99328980
--- /dev/null
+++ b/core/mocks/generated/trezorapp/__init__.pyi
@@ -0,0 +1,64 @@
+from typing import *
+from buffer_types import *
+
+
+# upymod/modtrezorapp/modtrezorapp-image.h
+class AppImage:
+    """
+    Application image image.
+    """
+
+    def write(self, offset: int, data: AnyBytes) -> None
+        """
+        Writes data to the application image at the specified offset.
+        """
+
+    def finalize(self, bool accept) -> None:
+        """
+    Finalizes loading of the application image. If `accept` is true,
+    the image is marked as loaded and will be available for execution.
+    If `accept` is false, the image is discarded.
+        """
+
+
+# upymod/modtrezorapp/modtrezorapp-task.h
+class AppTask:
+    """
+    App task structure.
+    """
+
+    def id(self) -> int:
+        """
+        Returns the task id.
+        """
+
+    def is_running(self) -> bool:
+        """
+        Returns whether the application is still running.
+        """
+
+    def unload(self) -> None:
+        """
+        Unloads the application associated with this task.
+        """
+
+
+# upymod/modtrezorapp/modtrezorapp.c
+def spawn_task(app_hash: bytes) -> AppTask:
+    """
+    Spawns an application task from the app cache.
+    """
+
+
+# upymod/modtrezorapp/modtrezorapp.c
+def create_image(app_hash: bytes, size: int) -> AppImage:
+    """
+    Creates a new application image in the app cache.
+    """
+
+
+# upymod/modtrezorapp/modtrezorapp.c
+def load_file(app_hash: bytes, filename: Str) -> None:
+    """
+    Loads an application image from a file into the app cache.
+    """
diff --git a/core/mocks/generated/trezorio/__init__.pyi b/core/mocks/generated/trezorio/__init__.pyi
index 1e87541e..e09e8b4d 100644
--- a/core/mocks/generated/trezorio/__init__.pyi
+++ b/core/mocks/generated/trezorio/__init__.pyi
@@ -113,7 +113,7 @@ class USB:
         """
         Cleans up the USB stack.
         """
-from . import fatfs, haptic, sdcard, ble, pm, rgb_led, ipc
+from . import fatfs, haptic, sdcard, ble, pm, rgb_led, ipc, app_cache
 POLL_READ: int  # wait until interface is readable and return read data
 POLL_WRITE: int  # wait until interface is writable
 
diff --git a/core/mocks/generated/trezorutils.pyi b/core/mocks/generated/trezorutils.pyi
index 62bab0e8..d59a0c5f 100644
--- a/core/mocks/generated/trezorutils.pyi
+++ b/core/mocks/generated/trezorutils.pyi
@@ -266,6 +266,8 @@ USE_NRF: bool
 """Whether the hardware has a nRF chip."""
 USE_DBG_CONSOLE: bool
 """Whether a debug console is enabled."""
+USE_APP_LOADING: bool
+"""Whether the firmware supports loading 3rd-party applications."""
 MODEL: str
 """Model name."""
 MODEL_FULL_NAME: str
diff --git a/core/src/trezor/__init__.py b/core/src/trezor/__init__.py
index 3fab1c84..70d6a6a9 100644
--- a/core/src/trezor/__init__.py
+++ b/core/src/trezor/__init__.py
@@ -4,3 +4,8 @@ import trezorio as io  # noqa: F401
 import trezortranslate as translations  # noqa: F401
 
 TR = translations.TR
+
+from . import utils
+
+if utils.USE_APP_LOADING:
+    import trezorapp as app  # noqa: F401
diff --git a/core/src/trezor/utils.py b/core/src/trezor/utils.py
index 95cf0f44..062be0a3 100644
--- a/core/src/trezor/utils.py
+++ b/core/src/trezor/utils.py
@@ -21,6 +21,7 @@ from trezorutils import (  # noqa: F401
     NOTIFY_WIPE,
     SCM_REVISION,
     UI_LAYOUT,
+    USE_APP_LOADING,
     USE_BACKLIGHT,
     USE_BLE,
     USE_BUTTON,