diff --git a/README.md b/README.md
index bb4ac68..9540928 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ Coldcard is a Cheap, Ultra-secure & Opensource Hardware Wallet for #Bitcoin.
 
 Get yours at [ColdcardWallet.com](http://coldcardwallet.com)
 
-This is the python code and command-line utilities you need to communciate with it over USB.
+This is the python code and command-line utilities you need to communicate with it over USB.
 
 ## Setup For Everyday Use
 
diff --git a/ckcc/cli.py b/ckcc/cli.py
index 08281bb..a98ce0f 100755
--- a/ckcc/cli.py
+++ b/ckcc/cli.py
@@ -205,7 +205,7 @@ def real_file_upload(fd, blksize=MAX_BLK_LEN, do_upgrade=False, do_reboot=True,
 
             magic = struct.unpack_from("<I", hdr)[0]
             #print("hdr @ 0x%x: %s" % (FW_HEADER_OFFSET, b2a_hex(hdr)))
-        except:
+        except Exception:
             magic = None
 
         if magic != FW_HEADER_MAGIC:
@@ -309,7 +309,7 @@ def get_pubkey(subpath):
 
     try:
         from pycoin.key.BIP32Node import BIP32Node
-    except:
+    except Exception:
         raise click.Abort("pycoin must be installed, not found.")
 
     dev = get_device()
@@ -410,7 +410,7 @@ def sign_message(message, path, verbose=True, just_sig=False, wrap=False, segwit
     # standard very much still in flux, see: <https://github.com/bitcoin/bitcoin/issues/10542>
 
     # not enforcing policy here on msg contents, so we can define that on product
-    message = message.encode('ascii')
+    message = message.encode('ascii') if not isinstance(message, bytes) else message
 
     ok = dev.send_recv(CCProtocolPacker.sign_message(message, path, addr_fmt), timeout=None)
     assert ok == None
diff --git a/ckcc/client.py b/ckcc/client.py
index 6610cd4..1b77a9a 100644
--- a/ckcc/client.py
+++ b/ckcc/client.py
@@ -161,10 +161,10 @@ class ColdcardDevice:
                 print("Rx [%2d]: %r" % (len(resp), b2a_hex(bytes(resp))))
 
             return CCProtocolUnpacker.decode(resp)
-        except CCProtoError as e:
+        except CCProtoError:
             if expect_errors: raise
             raise
-        except:
+        except Exception:
             #print("Corrupt response: %r" % resp)
             raise
 
@@ -260,7 +260,8 @@ class ColdcardDevice:
 
         # If Pycoin is not available, do it using ecdsa
         from ecdsa import BadSignatureError, SECP256k1, VerifyingKey
-        pubkey, chaincode = decode_xpub(expected_xpub)
+        # of the returned (pubkey, chaincode) tuple, chaincode is not used
+        pubkey, _ = decode_xpub(expected_xpub)
         vk = VerifyingKey.from_string(get_pubkey_string(pubkey), curve=SECP256k1)
         try:
             ok = vk.verify_digest(sig[1:], self.session_key)
@@ -346,7 +347,7 @@ class UnixSimulatorPipe:
         self.pipe = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
         try:
             self.pipe.connect(path)
-        except:
+        except Exception:
             self.close()
             raise RuntimeError("Cannot connect to simulator. Is it running?")
 
@@ -388,7 +389,8 @@ class UnixSimulatorPipe:
         self.pipe.close()
         try:
             os.unlink(self.pipe_name)
-        except: pass
+        except Exception:
+            pass
 
     def get_serial_number_string(self):
         return 'simulator'
diff --git a/ckcc/utils.py b/ckcc/utils.py
index 3f4e6e6..5389293 100644
--- a/ckcc/utils.py
+++ b/ckcc/utils.py
@@ -24,14 +24,14 @@ def dfu_parse(fd):
 
     assert dfu_prefix.signature == b'DfuSe', "Not a DFU file (bad magic)"
 
-    for idx in range(dfu_prefix.targets):
+    for _ in range(dfu_prefix.targets):
 
         prefix = consume(fd, 'Target', '<6sBI255s2I', 
                                    'signature altsetting named name size elements')
 
         #print("target%d: %r" % (idx, prefix))
 
-        for ei in range(prefix.elements):
+        for _ in range(prefix.elements):
             # Decode target prefix
             #   <   little endian
             #   I   uint32_t    element address