diff -Nru tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/debian/changelog tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/debian/changelog
--- tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/debian/changelog	2021-01-12 12:02:14.000000000 +0000
+++ tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/debian/changelog	2021-01-13 14:17:21.000000000 +0000
@@ -1,8 +1,15 @@
-tt-bandwidth-manager-gui (0.3.4~ubuntu18.04.1) bionic; urgency=low
+tt-bandwidth-manager-gui (0.3.5~ubuntu18.04.1) bionic; urgency=low
 
   * Auto build.
 
- -- Nate <nate_marti@sil.org>  Tue, 12 Jan 2021 12:02:14 +0000
+ -- Nate <nate_marti@sil.org>  Wed, 13 Jan 2021 14:17:21 +0000
+
+tt-bandwidth-manager-gui (0.3.5) focal; urgency=medium
+
+  * Fix missing timestamp when 'systemctl show' returns an error.
+  * Show return codes for subprocess commands.
+
+ -- Nate Marti <nate_marti@sil.org>  Wed, 13 Jan 2021 14:58:14 +0100
 
 tt-bandwidth-manager-gui (0.3.4) focal; urgency=medium
 
diff -Nru tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/debian/git-build-recipe.manifest tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/debian/git-build-recipe.manifest
--- tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/debian/git-build-recipe.manifest	2021-01-12 12:02:14.000000000 +0000
+++ tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/debian/git-build-recipe.manifest	2021-01-13 14:17:21.000000000 +0000
@@ -1,2 +1,2 @@
 # git-build-recipe format 0.4 deb-version {debversion}
-lp:tt-bandwidth-manager-gui git-commit:4fb609b22e058fc82cbbc623ab6a648cf4281dee
+lp:tt-bandwidth-manager-gui git-commit:5ad59c0377d940deedecab47753838034d47d61d
diff -Nru tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/app.py tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/app.py
--- tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/app.py	2021-01-12 12:02:14.000000000 +0000
+++ tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/app.py	2021-01-13 14:17:21.000000000 +0000
@@ -161,19 +161,17 @@
             "--no-pager",
         ]
         status_output = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+        utils.print_result(cmd, status_output)
         if status_output.returncode != 0:
             # Status output error. Probably due to kernel incompatibility after update.
             #   Fall back to trying "systemctl status" command instead.
             self.unit_file_state = 'unknown'
             self.active_state = 'unknown'
             self.svc_start_time = 'unknown'
-            cmd = [
-                "systemctl",
-                "status",
-                "tt-bandwidth-manager.service",
-                "--no-pager",
-            ]
+            cmd.pop(1)
+            cmd.insert(1, "status")
             status_output = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+            utils.print_result(cmd, status_output)
             output_list = status_output.stdout.decode().splitlines()
             #print(output_list)
             upat = '\s+Loaded: loaded \(/etc/systemd/system/tt-bandwidth-manager.service; (.*);.*'
@@ -296,19 +294,22 @@
 
     def stop_service(self):
         cmd = ["systemctl", "stop", "tt-bandwidth-manager.service"]
-        subprocess.run(cmd)
+        result = subprocess.run(cmd)
+        utils.print_result(cmd, result)
         self.update_info_widgets()
 
     def start_service(self):
         cmd = ["systemctl", "start", "tt-bandwidth-manager.service"]
-        subprocess.run(cmd)
+        result = subprocess.run(cmd)
+        utils.print_result(cmd, result)
         self.tt_pid, self.tt_start, self.tt_dev = utils.wait_for_tt_start()
         self.update_info_widgets()
         self.treeview_config = self.update_treeview_config()
 
     def restart_service(self):
         cmd = ["systemctl", "restart", "tt-bandwidth-manager.service"]
-        subprocess.run(cmd)
+        result = subprocess.run(cmd)
+        utils.print_result(cmd, result)
         self.tt_pid, self.tt_start, self.tt_dev = utils.wait_for_tt_start()
         # Check service status and update widgets.
         self.update_info_widgets()
diff -Nru tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/utils.py tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/utils.py
--- tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/utils.py	2021-01-12 12:02:14.000000000 +0000
+++ tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/utils.py	2021-01-13 14:17:21.000000000 +0000
@@ -21,6 +21,9 @@
             output = func(*args, **kwargs)
     return output
 
+def print_result(cmd, result):
+    print(f"'{' '.join(cmd)}' -> {result.returncode}")
+
 def get_net_device():
     '''
     Return the gateway internet device.
diff -Nru tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/worker.py tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/worker.py
--- tt-bandwidth-manager-gui-0.3.4~ubuntu18.04.1/trafficcop/worker.py	2021-01-12 12:02:14.000000000 +0000
+++ tt-bandwidth-manager-gui-0.3.5~ubuntu18.04.1/trafficcop/worker.py	2021-01-13 14:17:21.000000000 +0000
@@ -28,17 +28,19 @@
         "--no-pager",
         "--since=\'" + app.app.svc_start_time + "\'",
     ]
+    if app.app.svc_start_time == 'unknown':
+        # Likely due to a kernel/systemd incompatibility.
+        cmd.pop() # to remove the "--since" option
     cmd_txt = " ".join(cmd)
-    subprocess.run(cmd_txt, shell=True)
+    result = subprocess.run(cmd_txt, shell=True)
+    print(f"{cmd} -> {result.returncode}")
     return
 
 def handle_button_config_clicked():
     # Open config file in gedit.
-    subprocess.run(
-        ["gedit", "/etc/tt-config.yaml"],
-        stdout=subprocess.PIPE,
-        stderr=subprocess.STDOUT,
-    )
+    cmd = ["gedit", "/etc/tt-config.yaml"]
+    result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    utils.print_result(cmd, result)
 
 def handle_config_changed():
     pass