diff --git a/tools/encfs_aes_getpass.py b/tools/encfs_aes_getpass.py
index 31a526f0d..56c8314e8 100755
--- a/tools/encfs_aes_getpass.py
+++ b/tools/encfs_aes_getpass.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python3
-from __future__ import print_function
-
 '''
 Use TREZOR as a hardware key for opening EncFS filesystem!
 
@@ -62,7 +60,7 @@ def choose_device(devices):
     try:
         device_id = int(input())
         return devices[device_id]
-    except:
+    except Exception:
         raise ValueError("Invalid choice, exiting...")
 
 
diff --git a/tools/mem_flashblock.py b/tools/mem_flashblock.py
index 6de4f7a8a..1df65dead 100755
--- a/tools/mem_flashblock.py
+++ b/tools/mem_flashblock.py
@@ -2,7 +2,6 @@
 from trezorlib.debuglink import DebugLink
 from trezorlib.client import TrezorClient
 from trezorlib.transport import enumerate_devices
-import binascii
 import sys
 
 sectoraddrs = [0x8000000, 0x8004000, 0x8008000, 0x800c000,
diff --git a/tools/rng_entropy_collector.py b/tools/rng_entropy_collector.py
index 1f4dcbcde..421ecd59c 100755
--- a/tools/rng_entropy_collector.py
+++ b/tools/rng_entropy_collector.py
@@ -4,7 +4,6 @@
 # that has DEBUG_RNG == 1 as that will disable the user button
 # push confirmation
 
-from __future__ import print_function
 import io
 import sys
 from trezorlib.client import TrezorClient
diff --git a/trezorctl b/trezorctl
index cb65ea328..c1c30d0bc 100755
--- a/trezorctl
+++ b/trezorctl
@@ -96,10 +96,10 @@ def cli(ctx, path, verbose, is_json):
     def get_device():
         try:
             device = get_transport(path, prefix_search=False)
-        except:
+        except Exception:
             try:
                 device = get_transport(path, prefix_search=True)
-            except:
+            except Exception:
                 click.echo("Failed to find a TREZOR device.")
                 if path is not None:
                     click.echo("Using path: {}".format(path))
diff --git a/trezorlib/cosi.py b/trezorlib/cosi.py
index e2a95f363..216f27517 100644
--- a/trezorlib/cosi.py
+++ b/trezorlib/cosi.py
@@ -21,7 +21,7 @@ from typing import Iterable, Tuple
 from . import messages
 from .tools import expect
 
-from trezorlib import _ed25519
+from . import _ed25519
 
 # XXX, these could be NewType's, but that would infect users of the cosi module with these types as well.
 # Unsure if we want that.
@@ -90,7 +90,7 @@ def sign_with_privkey(digest: bytes, privkey: Ed25519PrivateKey,
     return Ed25519Signature(_ed25519.encodeint(S))
 
 
-### Client functions ###
+# ====== Client functions ====== #
 
 
 @expect(messages.CosiCommitment)
diff --git a/trezorlib/ethereum.py b/trezorlib/ethereum.py
index 41a147f71..fcf1d91b5 100644
--- a/trezorlib/ethereum.py
+++ b/trezorlib/ethereum.py
@@ -6,7 +6,7 @@ def int_to_big_endian(value):
     return value.to_bytes((value.bit_length() + 7) // 8, 'big')
 
 
-### Client functions ###
+# ====== Client functions ====== #
 
 
 @expect(proto.EthereumAddress, field="address")
diff --git a/trezorlib/firmware.py b/trezorlib/firmware.py
index 905c9bc88..779ca1408 100644
--- a/trezorlib/firmware.py
+++ b/trezorlib/firmware.py
@@ -130,12 +130,12 @@ def validate_firmware(filename):
     try:
         cosi.verify(header.signature, digest, global_pk)
         print("Signature OK")
-    except:
+    except Exception:
         print("Signature FAILED")
         raise
 
 
-### Client functions ###
+# ====== Client functions ====== #
 
 
 @tools.session
diff --git a/trezorlib/nem.py b/trezorlib/nem.py
index ee4ca1e44..c72e42182 100644
--- a/trezorlib/nem.py
+++ b/trezorlib/nem.py
@@ -167,7 +167,7 @@ def create_sign_tx(transaction):
     return msg
 
 
-### Client functions ###
+# ====== Client functions ====== #
 
 
 @expect(proto.NEMAddress, field="address")
diff --git a/trezorlib/protocol_v1.py b/trezorlib/protocol_v1.py
index 592f4f230..fe2cf796e 100644
--- a/trezorlib/protocol_v1.py
+++ b/trezorlib/protocol_v1.py
@@ -14,8 +14,6 @@
 # You should have received a copy of the License along with this library.
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
-from __future__ import absolute_import
-
 from io import BytesIO
 import logging
 import struct
@@ -79,7 +77,7 @@ class ProtocolV1:
         try:
             headerlen = struct.calcsize('>HL')
             msg_type, datalen = struct.unpack('>HL', chunk[3:3 + headerlen])
-        except:
+        except Exception:
             raise RuntimeError('Cannot parse header')
 
         data = chunk[3 + headerlen:]
diff --git a/trezorlib/protocol_v2.py b/trezorlib/protocol_v2.py
index a9474ee21..97934767b 100644
--- a/trezorlib/protocol_v2.py
+++ b/trezorlib/protocol_v2.py
@@ -14,8 +14,6 @@
 # You should have received a copy of the License along with this library.
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
-from __future__ import absolute_import
-
 from io import BytesIO
 import logging
 import struct
@@ -110,7 +108,7 @@ class ProtocolV2:
         try:
             headerlen = struct.calcsize('>BLLL')
             magic, session, msg_type, datalen = struct.unpack('>BLLL', chunk[:headerlen])
-        except:
+        except Exception:
             raise RuntimeError('Cannot parse header')
         if magic != 0x01:
             raise RuntimeError('Unexpected magic character')
@@ -122,7 +120,7 @@ class ProtocolV2:
         try:
             headerlen = struct.calcsize('>BLL')
             magic, session, sequence = struct.unpack('>BLL', chunk[:headerlen])
-        except:
+        except Exception:
             raise RuntimeError('Cannot parse header')
         if magic != 0x02:
             raise RuntimeError('Unexpected magic characters')
@@ -134,7 +132,7 @@ class ProtocolV2:
         try:
             headerlen = struct.calcsize('>BL')
             magic, session = struct.unpack('>BL', chunk[:headerlen])
-        except:
+        except Exception:
             raise RuntimeError('Cannot parse header')
         if magic != 0x03:
             raise RuntimeError('Unexpected magic character')
diff --git a/trezorlib/qt/pinmatrix.py b/trezorlib/qt/pinmatrix.py
index 3603b589d..e6850cf0c 100644
--- a/trezorlib/qt/pinmatrix.py
+++ b/trezorlib/qt/pinmatrix.py
@@ -14,7 +14,6 @@
 # You should have received a copy of the License along with this library.
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
-from __future__ import print_function
 import sys
 import math
 
@@ -22,7 +21,7 @@ try:
     from PyQt4.QtGui import (QPushButton, QLineEdit, QSizePolicy, QRegExpValidator, QLabel,
                              QApplication, QWidget, QGridLayout, QVBoxLayout, QHBoxLayout)
     from PyQt4.QtCore import QObject, SIGNAL, QRegExp, Qt, QT_VERSION_STR
-except:
+except ImportError:
     from PyQt5.QtWidgets import (QPushButton, QLineEdit, QSizePolicy, QLabel,
                                  QApplication, QWidget, QGridLayout, QVBoxLayout, QHBoxLayout)
     from PyQt5.QtGui import QRegExpValidator
diff --git a/trezorlib/stellar.py b/trezorlib/stellar.py
index 62e080313..803246d8b 100644
--- a/trezorlib/stellar.py
+++ b/trezorlib/stellar.py
@@ -338,7 +338,7 @@ def _crc16_checksum(bytes):
     return crc & 0xffff
 
 
-### Client functions ###
+# ====== Client functions ====== #
 
 
 @expect(messages.StellarPublicKey, field="public_key")
diff --git a/trezorlib/transport/bridge.py b/trezorlib/transport/bridge.py
index b225acc03..98c03647f 100644
--- a/trezorlib/transport/bridge.py
+++ b/trezorlib/transport/bridge.py
@@ -59,7 +59,7 @@ class BridgeTransport(Transport):
             if r.status_code != 200:
                 raise TransportException('trezord: Could not enumerate devices' + get_error(r))
             return [BridgeTransport(dev) for dev in r.json()]
-        except:
+        except Exception:
             return []
 
     def open(self):
diff --git a/trezorlib/transport/udp.py b/trezorlib/transport/udp.py
index 25b4f8110..02a1fdda2 100644
--- a/trezorlib/transport/udp.py
+++ b/trezorlib/transport/udp.py
@@ -95,7 +95,7 @@ class UdpTransport(Transport):
         try:
             self.socket.sendall(b'PINGPING')
             resp = self.socket.recv(8)
-        except:
+        except Exception:
             pass
         return resp == b'PONGPONG'
 
diff --git a/trezorlib/tx_api.py b/trezorlib/tx_api.py
index f72ad63ab..c827c86ca 100644
--- a/trezorlib/tx_api.py
+++ b/trezorlib/tx_api.py
@@ -52,7 +52,7 @@ class TxApi(object):
             try:  # looking into cache first
                 j = json.load(open(cache_file), parse_float=str)
                 return j
-            except:
+            except Exception:
                 pass
 
         if not self.url:
@@ -62,12 +62,12 @@ class TxApi(object):
             url = self.get_url(resource, resourceid)
             r = requests.get(url, headers={'User-agent': 'Mozilla/5.0'})
             j = r.json(parse_float=str)
-        except:
+        except Exception:
             raise RuntimeError('URL error: %s' % url)
         if cache_dir and cache_file:
             try:  # saving into cache
                 json.dump(j, open(cache_file, 'w'))
-            except:
+            except Exception:
                 pass
         return j