diff --git a/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerJob.py b/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerJob.py
index 906c20dd25..a1460cca3f 100644
--- a/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerJob.py
+++ b/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerJob.py
@@ -44,7 +44,6 @@ class FirmwareUpdateCheckerJob(Job):
             result = response.read().decode("utf-8")
         except URLError:
             Logger.log("w", "Could not reach '{0}', if this URL is old, consider removal.".format(url))
-
         return result
 
     def parseVersionResponse(self, response: str) -> Version:
diff --git a/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerLookup.py b/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerLookup.py
index a21ad3f0e5..c78e6f6025 100644
--- a/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerLookup.py
+++ b/plugins/FirmwareUpdateChecker/FirmwareUpdateCheckerLookup.py
@@ -18,7 +18,7 @@ class FirmwareUpdateCheckerLookup:
         self._machine_id = machine_json.get("id")
         self._machine_name = machine_name.lower()  # Lower in-case upper-case chars are added to the original json.
         self._check_urls = []  # type:List[str]
-        for check_url in machine_json.get("check_urls"):
+        for check_url in machine_json.get("check_urls", []):
             self._check_urls.append(check_url)
         self._redirect_user = machine_json.get("update_url")
 
diff --git a/plugins/FirmwareUpdateChecker/tests/TestFirmwareUpdateChecker.py b/plugins/FirmwareUpdateChecker/tests/TestFirmwareUpdateChecker.py
index 21d15922a2..8cd7083f16 100644
--- a/plugins/FirmwareUpdateChecker/tests/TestFirmwareUpdateChecker.py
+++ b/plugins/FirmwareUpdateChecker/tests/TestFirmwareUpdateChecker.py
@@ -2,10 +2,8 @@
 # Cura is released under the terms of the LGPLv3 or higher.
 
 import pytest
-import json
 
-import unittest.mock
-from cura.CuraApplication import CuraApplication
+from unittest.mock import MagicMock
 
 from UM.Version import Version
 
@@ -18,7 +16,7 @@ json_data = \
             {
                 "id": 1,
                 "name": "ned",
-                "check_urls": ["http://urlecho.appspot.com/echo?status=200&body=5.1.2.3"],
+                "check_urls": [""],
                 "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware",
                 "version_parser": "default"
             },
@@ -26,7 +24,7 @@ json_data = \
             {
                 "id": 3,
                 "name": "olivia",
-                "check_urls": ["http://urlecho.appspot.com/echo?status=200&body=4.3.2.1", "https://this-url-clearly-doesnt-exist.net"],
+                "check_urls": [""],
                 "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware",
                 "version_parser": "default"
             },
@@ -34,15 +32,12 @@ json_data = \
             {
                 "id": 5,
                 "name": "emmerson",
-                "check_urls": ["http://urlecho.appspot.com/echo?status=200&body=0.2.2.2", "http://urlecho.appspot.com/echo?status=200&body=6.7.8.1"],
+                "check_urls": [""],
                 "update_url": "https://ultimaker.com/en/resources/20500-upgrade-firmware",
                 "version_parser": "default"
             }
     }
 
-def dummyCallback():
-    pass
-
 @pytest.mark.parametrize("name, id", [
     ("ned"     , 1),
     ("olivia"  , 3),
@@ -63,7 +58,6 @@ def test_FirmwareUpdateCheckerLookup(id, name):
 ])
 def test_FirmwareUpdateCheckerJob_getCurrentVersion(name, version):
     machine_data = json_data.get(name)
-    job = FirmwareUpdateCheckerJob(False, name, machine_data, dummyCallback)
-    job._headers = {"User-Agent": "Cura-UnitTests 0"}
-
+    job = FirmwareUpdateCheckerJob(False, name, machine_data, MagicMock)
+    job.getUrlResponse = MagicMock(return_value = str(version))  # Pretend like we got a good response from the server
     assert job.getCurrentVersion() == version