diff --git a/embed/extmod/modtrezorconfig/modtrezorconfig.c b/embed/extmod/modtrezorconfig/modtrezorconfig.c
index b93e502b8..8de2c5a7b 100644
--- a/embed/extmod/modtrezorconfig/modtrezorconfig.c
+++ b/embed/extmod/modtrezorconfig/modtrezorconfig.c
@@ -25,46 +25,58 @@
 
 #include "embed/extmod/trezorobj.h"
 
-#include "norcow.h"
 #include "storage.h"
 
-/// def init() -> None:
+STATIC mp_obj_t ui_wait_callback = mp_const_none;
+
+STATIC void wrapped_ui_wait_callback(uint32_t wait, uint32_t progress) {
+    if (mp_obj_is_callable(ui_wait_callback)) {
+        mp_call_function_2(ui_wait_callback, mp_obj_new_int(wait), mp_obj_new_int(progress));
+    }
+}
+
+/// def init(ui_wait_callback: (int, int -> None)=None) -> None:
 ///     '''
 ///     Initializes the storage.  Must be called before any other method is
 ///     called from this module!
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_init(void) {
-    storage_init();
+STATIC mp_obj_t mod_trezorconfig_init(size_t n_args, const mp_obj_t *args) {
+    if (n_args > 0) {
+        ui_wait_callback = args[0];
+        storage_init(wrapped_ui_wait_callback);
+    } else {
+        storage_init(NULL);
+    }
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_init_obj, mod_trezorconfig_init);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_init_obj, 0, 1, mod_trezorconfig_init);
 
-/// def check_pin(pin: int, waitcallback: (int, int -> None)) -> bool:
+/// def check_pin(pin: int) -> bool:
 ///     '''
 ///     Check the given PIN. Returns True on success, False on failure.
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_check_pin(mp_obj_t pin, mp_obj_t waitcallback) {
+STATIC mp_obj_t mod_trezorconfig_check_pin(mp_obj_t pin) {
     uint32_t pin_i = trezor_obj_get_uint(pin);
-    if (sectrue != storage_check_pin(pin_i, waitcallback)) {
+    if (sectrue != storage_check_pin(pin_i)) {
         return mp_const_false;
     }
     return mp_const_true;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorconfig_check_pin_obj, mod_trezorconfig_check_pin);
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorconfig_check_pin_obj, mod_trezorconfig_check_pin);
 
-/// def unlock(pin: int, waitcallback: (int, int -> None)) -> bool:
+/// def unlock(pin: int) -> bool:
 ///     '''
 ///     Attempts to unlock the storage with given PIN.  Returns True on
 ///     success, False on failure.
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_unlock(mp_obj_t pin, mp_obj_t waitcallback) {
+STATIC mp_obj_t mod_trezorconfig_unlock(mp_obj_t pin) {
     uint32_t pin_i = trezor_obj_get_uint(pin);
-    if (sectrue != storage_unlock(pin_i, waitcallback)) {
+    if (sectrue != storage_unlock(pin_i)) {
         return mp_const_false;
     }
     return mp_const_true;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorconfig_unlock_obj, mod_trezorconfig_unlock);
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_trezorconfig_unlock_obj, mod_trezorconfig_unlock);
 
 /// def has_pin() -> bool:
 ///     '''
@@ -78,19 +90,19 @@ STATIC mp_obj_t mod_trezorconfig_has_pin(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_trezorconfig_has_pin_obj, mod_trezorconfig_has_pin);
 
-/// def change_pin(pin: int, newpin: int, waitcallback: (int, int -> None)) -> bool:
+/// def change_pin(pin: int, newpin: int) -> bool:
 ///     '''
 ///     Change PIN. Returns True on success, False on failure.
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_change_pin(mp_obj_t pin, mp_obj_t newpin, mp_obj_t waitcallback) {
+STATIC mp_obj_t mod_trezorconfig_change_pin(mp_obj_t pin, mp_obj_t newpin) {
     uint32_t pin_i = trezor_obj_get_uint(pin);
     uint32_t newpin_i = trezor_obj_get_uint(newpin);
-    if (sectrue != storage_change_pin(pin_i, newpin_i, waitcallback)) {
+    if (sectrue != storage_change_pin(pin_i, newpin_i)) {
         return mp_const_false;
     }
     return mp_const_true;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorconfig_change_pin_obj, mod_trezorconfig_change_pin);
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorconfig_change_pin_obj, mod_trezorconfig_change_pin);
 
 /// def get(app: int, key: int, public: bool=False) -> bytes:
 ///     '''
diff --git a/embed/extmod/modtrezorconfig/norcow.c b/embed/extmod/modtrezorconfig/norcow.c
index 83afd6ac2..ed54be3b2 100644
--- a/embed/extmod/modtrezorconfig/norcow.c
+++ b/embed/extmod/modtrezorconfig/norcow.c
@@ -20,17 +20,8 @@
 #include <string.h>
 
 #include "norcow.h"
-
-#include "common.h"
 #include "flash.h"
-
-#if TREZOR_MODEL == T
-#define NORCOW_SECTORS  {FLASH_SECTOR_STORAGE_1, FLASH_SECTOR_STORAGE_2}
-#elif TREZOR_MODEL == 1
-#define NORCOW_SECTORS  {2, 3}
-#else
-#error Unknown TREZOR Model
-#endif
+#include "common.h"
 
 // NRCW = 4e524357
 #define NORCOW_MAGIC      ((uint32_t)0x5743524e)
@@ -233,6 +224,7 @@ static void compact()
  */
 void norcow_init(void)
 {
+    flash_init();
     secbool found = secfalse;
     // detect active sector - starts with magic
     for (uint8_t i = 0; i < NORCOW_SECTOR_COUNT; i++) {
diff --git a/embed/extmod/modtrezorconfig/norcow.h b/embed/extmod/modtrezorconfig/norcow.h
index 77320024a..00bab4d0a 100644
--- a/embed/extmod/modtrezorconfig/norcow.h
+++ b/embed/extmod/modtrezorconfig/norcow.h
@@ -24,17 +24,10 @@
 #include "secbool.h"
 
 /*
- * Storage parameters:
+ * Storage parameters
  */
 
-#define NORCOW_SECTOR_COUNT  2
-#if TREZOR_MODEL == T
-#define NORCOW_SECTOR_SIZE   (64*1024)
-#elif TREZOR_MODEL == 1
-#define NORCOW_SECTOR_SIZE   (16*1024)
-#else
-#error Unknown TREZOR Model
-#endif
+#include "norcow_config.h"
 
 /*
  * Initialize storage
diff --git a/embed/extmod/modtrezorconfig/norcow_config.h b/embed/extmod/modtrezorconfig/norcow_config.h
new file mode 100644
index 000000000..d792776d5
--- /dev/null
+++ b/embed/extmod/modtrezorconfig/norcow_config.h
@@ -0,0 +1,43 @@
+/*
+ * 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/>.
+ */
+
+#ifndef __NORCOW_CONFIG_H__
+#define __NORCOW_CONFIG_H__
+
+#include "flash.h"
+
+#define NORCOW_SECTOR_COUNT  2
+
+#if TREZOR_MODEL == T
+
+#define NORCOW_SECTOR_SIZE  (64*1024)
+#define NORCOW_SECTORS      {FLASH_SECTOR_STORAGE_1, FLASH_SECTOR_STORAGE_2}
+
+#elif TREZOR_MODEL == 1
+
+#define NORCOW_SECTOR_SIZE  (16*1024)
+#define NORCOW_SECTORS      {2, 3}
+
+#else
+
+#error Unknown TREZOR Model
+
+#endif
+
+#endif
diff --git a/embed/extmod/modtrezorconfig/storage.c b/embed/extmod/modtrezorconfig/storage.c
index 6f1a4b19e..39f6753c5 100644
--- a/embed/extmod/modtrezorconfig/storage.c
+++ b/embed/extmod/modtrezorconfig/storage.c
@@ -21,10 +21,7 @@
 
 #include "common.h"
 #include "norcow.h"
-#include "flash.h"
-
-#include "py/runtime.h"
-#include "py/obj.h"
+#include "storage.h"
 
 // Norcow storage key of configured PIN.
 #define PIN_KEY 0x0000
@@ -41,14 +38,15 @@
 
 static secbool initialized = secfalse;
 static secbool unlocked = secfalse;
+static PIN_UI_WAIT_CALLBACK ui_callback = NULL;
 
-void storage_init(void)
+void storage_init(PIN_UI_WAIT_CALLBACK callback)
 {
     initialized = secfalse;
     unlocked = secfalse;
-    flash_init();
     norcow_init();
     initialized = sectrue;
+    ui_callback = callback;
 }
 
 static secbool pin_fails_reset(uint16_t ofs)
@@ -131,7 +129,7 @@ static secbool pin_get_fails(const uint32_t **pinfail, uint32_t *pofs)
     return sectrue;
 }
 
-secbool storage_check_pin(uint32_t pin, mp_obj_t callback)
+secbool storage_check_pin(uint32_t pin)
 {
     const uint32_t *pinfail = NULL;
     uint32_t ofs;
@@ -151,20 +149,20 @@ secbool storage_check_pin(uint32_t pin, mp_obj_t callback)
     uint32_t progress;
     for (uint32_t wait = ~ctr; wait > 0; wait--) {
         for (int i = 0; i < 10; i++) {
-            if (mp_obj_is_callable(callback)) {
+            if (ui_callback) {
                 if ((~ctr) > 1000000) {  // precise enough
                     progress = (~ctr - wait) / ((~ctr) / 1000);
                 } else {
                     progress = ((~ctr - wait) * 10 + i) * 100 / (~ctr);
                 }
-                mp_call_function_2(callback, mp_obj_new_int(wait), mp_obj_new_int(progress));
+                ui_callback(wait, progress);
             }
             hal_delay(100);
         }
     }
     // Show last frame if we were waiting
-    if ((~ctr > 0) && mp_obj_is_callable(callback)) {
-        mp_call_function_2(callback, mp_obj_new_int(0), mp_obj_new_int(1000));
+    if ((~ctr > 0) && ui_callback) {
+        ui_callback(0, 1000);
     }
 
     // First, we increase PIN fail counter in storage, even before checking the
@@ -182,10 +180,10 @@ secbool storage_check_pin(uint32_t pin, mp_obj_t callback)
     return pin_fails_reset(ofs * sizeof(uint32_t));
 }
 
-secbool storage_unlock(const uint32_t pin, mp_obj_t callback)
+secbool storage_unlock(const uint32_t pin)
 {
     unlocked = secfalse;
-    if (sectrue == initialized && sectrue == storage_check_pin(pin, callback)) {
+    if (sectrue == initialized && sectrue == storage_check_pin(pin)) {
         unlocked = sectrue;
     }
     return unlocked;
@@ -223,12 +221,12 @@ secbool storage_has_pin(void)
     return sectrue == pin_cmp(1) ? secfalse : sectrue;
 }
 
-secbool storage_change_pin(const uint32_t pin, const uint32_t newpin, mp_obj_t callback)
+secbool storage_change_pin(const uint32_t oldpin, const uint32_t newpin)
 {
     if (sectrue != initialized || sectrue != unlocked) {
         return secfalse;
     }
-    if (sectrue != storage_check_pin(pin, callback)) {
+    if (sectrue != storage_check_pin(oldpin)) {
         return secfalse;
     }
     return norcow_set(PIN_KEY, &newpin, sizeof(uint32_t));
diff --git a/embed/extmod/modtrezorconfig/storage.h b/embed/extmod/modtrezorconfig/storage.h
index de6a38cf1..0a8944186 100644
--- a/embed/extmod/modtrezorconfig/storage.h
+++ b/embed/extmod/modtrezorconfig/storage.h
@@ -17,16 +17,22 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef __STORAGE_H__
+#define __STORAGE_H__
+
 #include <stdint.h>
 #include <stddef.h>
 #include "secbool.h"
-#include "py/obj.h"
 
-void storage_init(void);
+typedef void (*PIN_UI_WAIT_CALLBACK)(uint32_t wait, uint32_t progress);
+
+void storage_init(PIN_UI_WAIT_CALLBACK callback);
 void storage_wipe(void);
-secbool storage_check_pin(uint32_t pin, mp_obj_t callback);
-secbool storage_unlock(const uint32_t pin, mp_obj_t callback);
+secbool storage_check_pin(uint32_t pin);
+secbool storage_unlock(const uint32_t pin);
 secbool storage_has_pin(void);
-secbool storage_change_pin(const uint32_t pin, const uint32_t newpin, mp_obj_t callback);
+secbool storage_change_pin(const uint32_t oldpin, const uint32_t newpin);
 secbool storage_get(uint16_t key, const void **val, uint16_t *len);
 secbool storage_set(uint16_t key, const void *val, uint16_t len);
+
+#endif
diff --git a/src/apps/management/change_pin.py b/src/apps/management/change_pin.py
index 93bcb1bd3..2c554b8fb 100644
--- a/src/apps/management/change_pin.py
+++ b/src/apps/management/change_pin.py
@@ -2,7 +2,7 @@ from trezor import config, loop, ui, wire
 from trezor.messages import ButtonRequestType, MessageType
 from trezor.messages.ButtonRequest import ButtonRequest
 from trezor.messages.Success import Success
-from trezor.pin import pin_to_int, show_pin_timeout
+from trezor.pin import pin_to_int
 from trezor.ui.text import Text
 
 from apps.common.confirm import require_confirm
@@ -17,7 +17,7 @@ async def change_pin(ctx, msg):
     # get current pin, return failure if invalid
     if config.has_pin():
         curpin = await request_pin_ack(ctx)
-        if not config.check_pin(pin_to_int(curpin), show_pin_timeout):
+        if not config.check_pin(pin_to_int(curpin)):
             raise wire.PinInvalid("PIN invalid")
     else:
         curpin = ""
@@ -29,7 +29,7 @@ async def change_pin(ctx, msg):
         newpin = ""
 
     # write into storage
-    if not config.change_pin(pin_to_int(curpin), pin_to_int(newpin), show_pin_timeout):
+    if not config.change_pin(pin_to_int(curpin), pin_to_int(newpin)):
         raise wire.PinInvalid("PIN invalid")
 
     if newpin:
diff --git a/src/apps/management/load_device.py b/src/apps/management/load_device.py
index 4a2f9ba92..377a69843 100644
--- a/src/apps/management/load_device.py
+++ b/src/apps/management/load_device.py
@@ -27,6 +27,6 @@ async def load_device(ctx, msg):
     storage.load_mnemonic(mnemonic=msg.mnemonic, needs_backup=True, no_backup=False)
     storage.load_settings(use_passphrase=msg.passphrase_protection, label=msg.label)
     if msg.pin:
-        config.change_pin(pin_to_int(""), pin_to_int(msg.pin), None)
+        config.change_pin(pin_to_int(""), pin_to_int(msg.pin))
 
     return Success(message="Device loaded")
diff --git a/src/apps/management/recovery_device.py b/src/apps/management/recovery_device.py
index c9d311ac6..c95d29f21 100644
--- a/src/apps/management/recovery_device.py
+++ b/src/apps/management/recovery_device.py
@@ -55,7 +55,7 @@ async def recovery_device(ctx, msg):
     # save into storage
     if not msg.dry_run:
         if msg.pin_protection:
-            config.change_pin(pin_to_int(""), pin_to_int(newpin), None)
+            config.change_pin(pin_to_int(""), pin_to_int(newpin))
         storage.load_settings(label=msg.label, use_passphrase=msg.passphrase_protection)
         storage.load_mnemonic(mnemonic=mnemonic, needs_backup=False, no_backup=False)
         return Success(message="Device recovered")
diff --git a/src/apps/management/reset_device.py b/src/apps/management/reset_device.py
index e49274722..cd155cb34 100644
--- a/src/apps/management/reset_device.py
+++ b/src/apps/management/reset_device.py
@@ -65,7 +65,7 @@ async def reset_device(ctx, msg):
             await show_wrong_entry(ctx)
 
     # write PIN into storage
-    if not config.change_pin(pin_to_int(""), pin_to_int(newpin), None):
+    if not config.change_pin(pin_to_int(""), pin_to_int(newpin)):
         raise wire.ProcessError("Could not change PIN")
 
     # write settings and mnemonic into storage
diff --git a/src/boot.py b/src/boot.py
index 89b1427e8..622562152 100644
--- a/src/boot.py
+++ b/src/boot.py
@@ -8,13 +8,13 @@ async def bootscreen():
     while True:
         try:
             if not config.has_pin():
-                config.unlock(pin_to_int(""), show_pin_timeout)
+                config.unlock(pin_to_int(""))
                 return
             await lockscreen()
             label = None
             while True:
                 pin = await request_pin(label)
-                if config.unlock(pin_to_int(pin), show_pin_timeout):
+                if config.unlock(pin_to_int(pin)):
                     return
                 else:
                     label = "Wrong PIN, enter again"
@@ -52,7 +52,7 @@ async def lockscreen():
     await ui.click()
 
 
-config.init()
+config.init(show_pin_timeout)
 ui.display.backlight(ui.BACKLIGHT_NONE)
 loop.schedule(bootscreen())
 loop.run()
diff --git a/tests/test_trezor.config.py b/tests/test_trezor.config.py
index aba890529..68ee5ac60 100644
--- a/tests/test_trezor.config.py
+++ b/tests/test_trezor.config.py
@@ -27,7 +27,7 @@ class TestConfig(unittest.TestCase):
     def test_wipe(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         config.set(1, 1, b'hello')
         config.set(1, 2, b'world')
         v0 = config.get(1, 1)
@@ -44,7 +44,7 @@ class TestConfig(unittest.TestCase):
         for _ in range(128):
             config.init()
             config.wipe()
-            self.assertEqual(config.unlock(pin_to_int(''), None), True)
+            self.assertEqual(config.unlock(pin_to_int('')), True)
             appid, key = random_entry()
             value = random.bytes(16)
             config.set(appid, key, value)
@@ -54,12 +54,12 @@ class TestConfig(unittest.TestCase):
                 config.set(appid, key, bytes())
         config.init()
         config.wipe()
-        self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000'), None), False)
+        self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000')), False)
 
     def test_public(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
 
         appid, key = random_entry()
 
@@ -85,25 +85,25 @@ class TestConfig(unittest.TestCase):
     def test_change_pin(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         with self.assertRaises(RuntimeError):
             config.set(PINAPP, PINKEY, b'value')
-        self.assertEqual(config.change_pin(pin_to_int('000'), pin_to_int('666'), None), False)
-        self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000'), None), True)
+        self.assertEqual(config.change_pin(pin_to_int('000'), pin_to_int('666')), False)
+        self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000')), True)
         self.assertEqual(config.get(PINAPP, PINKEY), bytes())
         config.set(1, 1, b'value')
         config.init()
-        self.assertEqual(config.unlock(pin_to_int('000'), None), True)
-        config.change_pin(pin_to_int('000'), pin_to_int(''), None)
+        self.assertEqual(config.unlock(pin_to_int('000')), True)
+        config.change_pin(pin_to_int('000'), pin_to_int(''))
         config.init()
-        self.assertEqual(config.unlock(pin_to_int('000'), None), False)
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('000')), False)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         self.assertEqual(config.get(1, 1), b'value')
 
     def test_set_get(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         for _ in range(32):
             appid, key = random_entry()
             value = random.bytes(128)
@@ -114,7 +114,7 @@ class TestConfig(unittest.TestCase):
     def test_compact(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         appid, key = 1, 1
         for _ in range(259):
             value = random.bytes(259)
@@ -125,7 +125,7 @@ class TestConfig(unittest.TestCase):
     def test_get_default(self):
         config.init()
         config.wipe()
-        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+        self.assertEqual(config.unlock(pin_to_int('')), True)
         for _ in range(128):
             appid, key = random_entry()
             value = config.get(appid, key)