diff --git a/libagent/device/trezor.py b/libagent/device/trezor.py
index 7440e21..5d7cccf 100644
--- a/libagent/device/trezor.py
+++ b/libagent/device/trezor.py
@@ -57,21 +57,25 @@ class Trezor(interface.Device):
         cli_handler = conn.callback_PinMatrixRequest
 
         def new_handler(msg):
-            if _is_open_tty(sys.stdin):
-                result = cli_handler(msg)  # CLI-based PIN handler
-            else:
-                scrambled_pin = _message_box(
-                    'Use the numeric keypad to describe number positions.\n'
-                    'The layout is:\n'
-                    '    7 8 9\n'
-                    '    4 5 6\n'
-                    '    1 2 3\n'
-                    'Please enter PIN:')
-                result = self._defs.PinMatrixAck(pin=scrambled_pin)
-            if not set(result.pin).issubset('123456789'):
-                raise self._defs.PinException(
-                    None, 'Invalid scrambled PIN: {!r}'.format(result.pin))
-            return result
+            try:
+                if _is_open_tty(sys.stdin):
+                    result = cli_handler(msg)  # CLI-based PIN handler
+                else:
+                    scrambled_pin = _message_box(
+                        'Use the numeric keypad to describe number positions.\n'
+                        'The layout is:\n'
+                        '    7 8 9\n'
+                        '    4 5 6\n'
+                        '    1 2 3\n'
+                        'Please enter PIN:')
+                    result = self._defs.PinMatrixAck(pin=scrambled_pin)
+                if not set(result.pin).issubset('123456789'):
+                    raise self._defs.PinException(
+                        None, 'Invalid scrambled PIN: {!r}'.format(result.pin))
+                return result
+            except:  # noqa
+                conn.init_device()
+                raise
 
         conn.callback_PinMatrixRequest = new_handler
 
@@ -81,20 +85,24 @@ class Trezor(interface.Device):
         cli_handler = conn.callback_PassphraseRequest
 
         def new_handler(msg):
-            if self.__class__.cached_passphrase_ack:
-                log.debug('re-using cached %s passphrase', self)
-                return self.__class__.cached_passphrase_ack
-
-            if _is_open_tty(sys.stdin):
-                # use CLI-based PIN handler
-                ack = cli_handler(msg)
-            else:
-                passphrase = _message_box('Please enter passphrase:')
-                passphrase = mnemonic.Mnemonic.normalize_string(passphrase)
-                ack = self._defs.PassphraseAck(passphrase=passphrase)
-
-            self.__class__.cached_passphrase_ack = ack
-            return ack
+            try:
+                if self.__class__.cached_passphrase_ack:
+                    log.debug('re-using cached %s passphrase', self)
+                    return self.__class__.cached_passphrase_ack
+
+                if _is_open_tty(sys.stdin):
+                    # use CLI-based PIN handler
+                    ack = cli_handler(msg)
+                else:
+                    passphrase = _message_box('Please enter passphrase:')
+                    passphrase = mnemonic.Mnemonic.normalize_string(passphrase)
+                    ack = self._defs.PassphraseAck(passphrase=passphrase)
+
+                self.__class__.cached_passphrase_ack = ack
+                return ack
+            except:  # noqa
+                conn.init_device()
+                raise
 
         conn.callback_PassphraseRequest = new_handler