diff --git a/tcllib/argparser.py b/tcllib/argparser.py
index 0d16e23..6a2366d 100644
--- a/tcllib/argparser.py
+++ b/tcllib/argparser.py
@@ -11,6 +11,7 @@ import webbrowser
 
 class DefaultParser(argparse.ArgumentParser):
     """argparse parser with some defaults set."""
+
     def __init__(self, appname, desc=None):
         """Set default name, description, epilogue, arguments."""
         homeurl = "https://github.com/mbirth/tcl_ota_check"
diff --git a/tcllib/credentials.py b/tcllib/credentials.py
index 8a6ec8c..06b0499 100644
--- a/tcllib/credentials.py
+++ b/tcllib/credentials.py
@@ -17,6 +17,7 @@ def get_creds():
     params = {base64.b64decode(key): base64.b64decode(val) for key, val in creds.items()}
     return params
 
+
 def get_creds2():
     """Return alternate authentication."""
     creds = {
diff --git a/tcllib/devices.py b/tcllib/devices.py
index 6885ce3..bcd8b97 100644
--- a/tcllib/devices.py
+++ b/tcllib/devices.py
@@ -2,6 +2,7 @@
 
 """Pseudo-devices for desktop/mobile requests"""
 
+
 class Device():
     """Generic pseudo-device class."""
     CLTP_STATES = {
@@ -60,18 +61,24 @@ class Device():
         # Throws exception when invalid mode given:
         self.ckot = self.CKOT_STATES[new_ckot]
 
+
 class MobileDevice(Device):
     """Generic mobile (i.e. OTA) device."""
+
     def __init__(self, curef="PRD-63117-011", fwver="AAO472"):
+        """Populate variables."""
         super().__init__(curef, fwver)
         self.imei = "3531510"
         self.set_cltp("MOBILE")
         self.set_mode("OTA")
         self.ua = "com.tcl.fota/5.1.0.2.0029.0, Android"
 
+
 class DesktopDevice(Device):
     """Generic desktop (i.e. full) device."""
+
     def __init__(self, curef="PRD-63117-011", fwver="AAA000"):
+        """Populate variables."""
         super().__init__(curef, fwver)
         self.imei = "543212345000000"
         self.set_cltp("DESKTOP")
diff --git a/tcllib/devlist.py b/tcllib/devlist.py
index da11a40..75dbaa0 100644
--- a/tcllib/devlist.py
+++ b/tcllib/devlist.py
@@ -32,6 +32,7 @@ def load_local_devicelist():
     except FileNotFoundError:
         return None, True
 
+
 def get_devicelist(force=False, output_diff=True):
     """Return device list from saved database."""
     old_prds, need_download = load_local_devicelist()
@@ -49,7 +50,9 @@ def get_devicelist(force=False, output_diff=True):
 
     return prds
 
+
 def print_versions_diff(old_data, new_data):
+    """Print version changes between old and new databases."""
     prd = new_data["curef"]
     if new_data["last_full"] != old_data["last_full"] and new_data["last_ota"] != old_data["last_ota"]:
         print("> {}: {} ⇨ {} (OTA: {} ⇨ {})".format(
@@ -64,8 +67,9 @@ def print_versions_diff(old_data, new_data):
     elif new_data["last_ota"] != old_data["last_ota"]:
         print("> {}: {} ⇨ {} (OTA)".format(prd, ansi.YELLOW_DARK + str(old_data["last_ota"]) + ansi.RESET, ansi.YELLOW + str(new_data["last_ota"]) + ansi.RESET))
 
+
 def print_prd_diff(old_prds, new_prds):
-    """Print changes between old and new databases."""
+    """Print PRD changes between old and new databases."""
     added_prds = [prd for prd in new_prds if prd not in old_prds]
     removed_prds = [prd for prd in old_prds if prd not in new_prds]
     for prd in removed_prds:
diff --git a/tcllib/dumpmgr.py b/tcllib/dumpmgr.py
index 18ea392..a24897e 100644
--- a/tcllib/dumpmgr.py
+++ b/tcllib/dumpmgr.py
@@ -17,6 +17,7 @@ from . import ansi
 
 class DumpMgrMixin:
     """A mixin component for XML dump management."""
+
     def __init__(self):
         """Populate dump file name."""
         self.last_dump_filename = None
diff --git a/tcllib/servervote.py b/tcllib/servervote.py
index 3faecf0..816d753 100644
--- a/tcllib/servervote.py
+++ b/tcllib/servervote.py
@@ -10,6 +10,7 @@ import numpy
 
 class ServerVoteMixin:
     """A mixin component for server sorting."""
+
     def __init__(self):
         """Populate server list and weighting variables."""
         self.g2master = None
diff --git a/tcllib/tclcheck.py b/tcllib/tclcheck.py
index 55f6a15..0bd2987 100644
--- a/tcllib/tclcheck.py
+++ b/tcllib/tclcheck.py
@@ -6,7 +6,7 @@
 """Tools to interface with TCL's update request API."""
 
 import time
-from collections import OrderedDict
+from collections import OrderedDict, defaultdict
 
 import requests
 from defusedxml import ElementTree
@@ -14,10 +14,16 @@ from defusedxml import ElementTree
 
 class TclCheckMixin:
     """A mixin component for TCL's update request API."""
-    def prep_check(self, device=None, https=True):
-        """Prepare URL and parameters for update request."""
+
+    def prep_check_url(self, https=True):
+        """Prepare URL for update request."""
         protocol = "https://" if https else "http://"
         url = protocol + self.g2master + "/check.php"
+        return url
+
+    def prep_check(self, device=None, https=True):
+        """Prepare URL and parameters for update request."""
+        url = self.prep_check_url(https)
         params = OrderedDict()
         if device:
             # Need to support both ways for now
@@ -60,28 +66,31 @@ class TclCheckMixin:
                 last_response = req
                 if req.status_code == 200:
                     self.master_server_vote_on_time(reqtime, reqtime_avg)
-                    req.encoding = "utf-8"    # Force encoding as server doesn't give one
+                    req.encoding = "utf-8"  # Force encoding as server doesn't give one
                     self.write_dump(req.text)
                     return req.text
-                elif req.status_code == 204:
-                    self.master_server_vote_on_time(reqtime, reqtime_avg)
-                    raise requests.exceptions.HTTPError("No update available.", response=req)
-                elif req.status_code == 404:
-                    self.master_server_vote_on_time(reqtime, reqtime_avg)
-                    raise requests.exceptions.HTTPError("No data for requested CUREF/FV combination.", response=req)
                 elif req.status_code not in [500, 502, 503]:
-                    self.master_server_downvote()
-                    req.raise_for_status()
-                    raise requests.exceptions.HTTPError("HTTP {}.".format(req.status_code), response=req)
+                    self.do_check_errorhandle(req, reqtime, reqtime_avg)
             except requests.exceptions.Timeout:
                 pass
             # Something went wrong, try a different server
             self.master_server_downvote()
             self.g2master = self.get_master_server()
-            protocol = "https://" if https else "http://"
-            url = protocol + self.g2master + "/check.php"
+            url = self.prep_check_url(https)
         raise requests.exceptions.RetryError("Max tries ({}) reached.".format(max_tries), response=last_response)
 
+    def do_check_errorhandle(self, req, reqtime, reqtime_avg):
+        """Handle non-HTTP 200 results for ``do_check``."""
+        errcodes = defaultdict(lambda: "HTTP {}.".format(req.status_code))
+        errcodes[204] = "No update available."
+        errcodes[404] = "No data for requested CUREF/FV combination."
+        if req.status_code in [204, 404]:
+            self.master_server_vote_on_time(reqtime, reqtime_avg)
+        elif req.status_code not in [500, 502, 503]:
+            self.master_server_downvote()
+            req.raise_for_status()
+        raise requests.exceptions.HTTPError(errcodes[req.status_code], response=req)
+
     @staticmethod
     def parse_check(xmlstr):
         """Parse output of ``do_check``."""
diff --git a/tcllib/tclchecksum.py b/tcllib/tclchecksum.py
index 9b60d78..66306f8 100644
--- a/tcllib/tclchecksum.py
+++ b/tcllib/tclchecksum.py
@@ -14,6 +14,7 @@ from . import credentials
 
 class TclChecksumMixin:
     """A mixin component for TCL's checksum API."""
+
     def do_checksum(self, encslave, address, uri):
         """Perform checksum request with given parameters."""
         url = "http://" + encslave + "/checksum.php"
diff --git a/tcllib/tclencheader.py b/tcllib/tclencheader.py
index 4499d63..33dde10 100644
--- a/tcllib/tclencheader.py
+++ b/tcllib/tclencheader.py
@@ -10,6 +10,7 @@ from . import credentials
 
 class TclEncHeaderMixin:
     """A mixin component for TCL's encrypted header API.."""
+
     def do_encrypt_header(self, encslave, address):
         """Perform encrypted header request with given parameters."""
         params = credentials.get_creds2()
diff --git a/tcllib/tclrequest.py b/tcllib/tclrequest.py
index 1014c52..465ebd2 100644
--- a/tcllib/tclrequest.py
+++ b/tcllib/tclrequest.py
@@ -40,12 +40,14 @@ from defusedxml import ElementTree
 
 VDKEY_B64Z = b"eJwdjwEOwDAIAr8kKFr//7HhmqXp8AIIDrYAgg8byiUXrwRJRXja+d6iNxu0AhUooDCN9rd6rDLxmGIakUVWo3IGCTRWqCAt6X4jGEIUAxgN0eYWnp+LkpHQAg/PsO90ELsy0Npm/n2HbtPndFgGEV31R9OmT4O4nrddjc3Qt6nWscx7e+WRHq5UnOudtjw5skuV09pFhvmqnOEIs4ljPeel1wfLYUF4\n"
 
+
 def get_salt():
     """Generate cryptographic salt."""
     millis = floor(time.time() * 1000)
     tail = "{:06d}".format(random.randint(0, 999999))
     return "{}{}".format(str(millis), tail)
 
+
 def get_vk2(params_dict, cltp):
     """Generate salted hash of API parameters."""
     params_dict["cltp"] = cltp
@@ -61,11 +63,12 @@ def get_vk2(params_dict, cltp):
     hexhash = engine.hexdigest()
     return hexhash
 
+
 class TclRequestMixin:
     """A mixin component for TCL's download request API."""
 
-    def do_request(self, curef, fvver, tvver, fw_id):
-        """Perform download request with given parameters."""
+    def prep_request(self, curef, fvver, tvver, fw_id):
+        """Prepare URL and device parameters for download request."""
         url = "https://" + self.g2master + "/download_request.php"
         params = OrderedDict()
         params["id"] = self.serid
@@ -83,7 +86,11 @@ class TclRequestMixin:
         if self.mode == self.MODE.FULL:
             params["foot"] = 1
         params["chnl"] = self.chnl.value
+        return url, params
 
+    def do_request(self, curef, fvver, tvver, fw_id):
+        """Perform download request with given parameters."""
+        url, params = self.prep_request(curef, fvver, tvver, fw_id)
         # print(repr(dict(params)))
         req = self.sess.post(url, data=params)
         if req.status_code == 200: