diff --git a/src/calibre/devices/mtp/driver.py b/src/calibre/devices/mtp/driver.py
index a92ad011df..68299022b2 100644
--- a/src/calibre/devices/mtp/driver.py
+++ b/src/calibre/devices/mtp/driver.py
@@ -552,9 +552,9 @@ class MTP_DEVICE(BASE):
                     self.upload_cover(parent, relpath, storage, mi, stream)
                     # Upload the apnx file
                     if self.is_kindle and self.get_pref('apnx').get('send', False):
-                      name = path[-1].rpartition('.')[0]
-                      debug('Uploading APNX file for', name)
-                      self.upload_apnx(parent, name, storage, mi, infile)
+                        name = path[-1].rpartition('.')[0]
+                        debug('Uploading APNX file for', name)
+                        self.upload_apnx(parent, name, storage, mi, infile)
                 except Exception:
                     import traceback
                     traceback.print_exc()
@@ -654,9 +654,8 @@ class MTP_DEVICE(BASE):
 
         try:
             pref = self.get_pref('apnx')
-
             custom_page_count = 0
-            cust_col_name = pref.get('custom_column_page_count', None)
+            cust_col_name = pref.get('custom_column_page_count')
             if cust_col_name:
                 try:
                     custom_page_count = int(mi.get(cust_col_name, 0))
@@ -665,7 +664,7 @@ class MTP_DEVICE(BASE):
 
             method = pref.get('method', 'fast')
 
-            cust_col_method = pref.get('custom_column_method', None)
+            cust_col_method = pref.get('custom_column_method')
             if cust_col_method:
                 try:
                     method = str(mi.get(cust_col_method)).lower()
@@ -682,17 +681,16 @@ class MTP_DEVICE(BASE):
             apnx_size = os.path.getsize(apnx_local_path)
 
             with open(apnx_local_path, 'rb') as apnx_stream:
-              apnx_filename = f'{name}.apnx'
-              apnx_path = parent.name, f'{name}.sdr', apnx_filename
-              sdr_parent = self.ensure_parent(storage, apnx_path)
-              self.put_file(sdr_parent, apnx_filename, apnx_stream, apnx_size)
-
+                apnx_filename = f'{name}.apnx'
+                apnx_path = parent.name, f'{name}.sdr', apnx_filename
+                sdr_parent = self.ensure_parent(storage, apnx_path)
+                self.put_file(sdr_parent, apnx_filename, apnx_stream, apnx_size)
         except Exception:
-            print('Failed to generate APNX')
+            print('Failed to generate APNX', file=sys.stderr)
             import traceback
             traceback.print_exc()
         finally:
-          os.remove(apnx_local_path)
+            os.remove(apnx_local_path)
         debug('upload_apnx() ended')
 
     def add_books_to_metadata(self, mtp_files, metadata, booklists):
diff --git a/src/calibre/gui2/device_drivers/mtp_config.py b/src/calibre/gui2/device_drivers/mtp_config.py
index 5d00077942..0166b8d2be 100644
--- a/src/calibre/gui2/device_drivers/mtp_config.py
+++ b/src/calibre/gui2/device_drivers/mtp_config.py
@@ -9,6 +9,7 @@ import weakref
 
 from qt.core import (
     QApplication,
+    QCheckBox,
     QComboBox,
     QDialog,
     QDialogButtonBox,
@@ -31,7 +32,6 @@ from qt.core import (
     QVBoxLayout,
     QWidget,
     pyqtSignal,
-    QCheckBox,
 )
 
 from calibre.ebooks import BOOK_EXTENSIONS
@@ -352,7 +352,8 @@ class FormatRules(QGroupBox):
                     yield r
 # }}}
 
-class APNX(QWidget):
+
+class APNX(QWidget):  # {{{
     def __init__(self, apnx):
         QWidget.__init__(self)
         self.layout = l = QVBoxLayout()
@@ -361,42 +362,45 @@ class APNX(QWidget):
         self.layout.setAlignment(Qt.AlignTop)
 
         self.send = f1 = QCheckBox(_('Send page number information when sending books'))
-        f1.setChecked(apnx.get('send', False))
+        f1.setChecked(bool(apnx.get('send')))
         l.addWidget(f1)
 
         label2 = QLabel('<p>' + _('Page count calculation method') + '</p>')
         label2.setWordWrap(True)
         l.addWidget(label2)
         self.method = f2 = QComboBox(self)
-        f2.addItem('fast', 'fast')
-        f2.addItem('accurate', 'accurate')
-        f2.addItem('pagebrek', 'pagebreak')
-        f2.setCurrentIndex(f2.findText(apnx.get('method', 'fast')))
+        f2.addItem(_('fast'), 'fast')
+        f2.addItem(_('accurate'), 'accurate')
+        f2.addItem(_('pagebreak'), 'pagebreak')
+        if (idx := f2.findData(apnx.get('method') or 'fast')) > -1:
+            f2.setCurrentIndex(idx)
         l.addWidget(f2)
 
         label3 = QLabel('<p>' + _('Custom column name to retrieve page counts from') + '</p>')
         label3.setWordWrap(True)
         l.addWidget(label3)
         self.column_page_count = f3 = QLineEdit(self)
-        f3.setText(apnx.get('custom_column_page_count', ''))
+        f3.setText(apnx.get('custom_column_page_count') or '')
         l.addWidget(f3)
 
         label4 = QLabel('<p>' + _('Custom column name to retrieve calculation method from') + '</p>')
         label4.setWordWrap(True)
         l.addWidget(label4)
         self.column_method = f4 = QLineEdit(self)
-        f4.setText(apnx.get('custom_column_method', ''))
+        f4.setText(apnx.get('custom_column_method') or '')
         l.addWidget(f4)
 
     @property
     def apnx(self):
         result = {
-            'send': self.send.isChecked(),
+            'send': bool(self.send.isChecked()),
             'method': str(self.method.currentData()).strip(),
             'custom_column_page_count': str(self.column_page_count.text()).strip(),
             'custom_column_method': str(self.column_method.text()).strip(),
         }
         return result
+# }}}
+
 
 class MTPConfig(QTabWidget):
 
@@ -467,9 +471,9 @@ class MTPConfig(QTabWidget):
             l.addWidget(r, 7, 0, 1, 2)
             l.setRowStretch(7, 100)
 
-            if self.device.is_kindle:
-              self.apnxTab = APNX(self.get_pref('apnx'))
-              self.addTab(self.apnxTab, _('Page numbering (APNX)'))
+            if device.is_kindle:
+                self.apnx_tab = APNX(self.get_pref('apnx') or {})
+                self.addTab(self.apnx_tab, _('Page numbering (APNX)'))
 
         self.igntab = IgnoredDevices(self.device.prefs['history'],
                 self.device.prefs['blacklist'])
@@ -560,7 +564,8 @@ class MTPConfig(QTabWidget):
                 p['ignored_folders'] = self.current_ignored_folders
 
             p.pop('apnx', None)
-            p['apnx'] = self.apnxTab.apnx
+            if hasattr(self, 'apnx_tab'):
+                p['apnx'] = self.apnx_tab.apnx
 
             if self.current_device_key is not None:
                 self.device.prefs[self.current_device_key] = p