diff --git a/includes/discovery/os/firebox.inc.php b/includes/discovery/os/firebox.inc.php
new file mode 100644
index 0000000000..11544847dd
--- /dev/null
+++ b/includes/discovery/os/firebox.inc.php
@@ -0,0 +1,5 @@
+<?php
+
+if (starts_with($sysDescr, 'WatchGuard Fireware') || starts_with($sysObjectId, '.1.3.6.1.4.1.3097.1.5')) {
+    $os = 'firebox';
+}
diff --git a/includes/discovery/os/waas.inc.php b/includes/discovery/os/waas.inc.php
index b0ec7876a4..797b020f0b 100644
--- a/includes/discovery/os/waas.inc.php
+++ b/includes/discovery/os/waas.inc.php
@@ -10,6 +10,6 @@
  * the source code distribution for details.
  */
 
-if (starts_with('Cisco Wide Area Application Services', $sysDescr)) {
+if (starts_with($sysDescr, 'Cisco Wide Area Application Services')) {
     $os = 'waas';
 }
diff --git a/includes/discovery/os/watchguard.inc.php b/includes/discovery/os/watchguard.inc.php
deleted file mode 100644
index ad5934b892..0000000000
--- a/includes/discovery/os/watchguard.inc.php
+++ /dev/null
@@ -1,5 +0,0 @@
-<?php
-
-if (starts_with('WatchGuard Fireware', $sysDescr) || starts_with('.1.3.6.1.4.1.3097.1.5', $sysObjectId)) {
-    $os = 'firebox';
-}
diff --git a/includes/discovery/os/webpower.inc.php b/includes/discovery/os/webpower.inc.php
index bea3df1b40..c8bc5a9d78 100644
--- a/includes/discovery/os/webpower.inc.php
+++ b/includes/discovery/os/webpower.inc.php
@@ -1,5 +1,5 @@
 <?php
 
-if (str_contains('.1.3.6.1.4.1.2468.1.2.1', $sysObjectId)) {
+if (str_contains($sysObjectId, '.1.3.6.1.4.1.2468.1.2.1')) {
     $os = 'webpower';
 }
diff --git a/includes/discovery/os/windows.inc.php b/includes/discovery/os/windows.inc.php
index 3b4b066487..ec7a02c4e0 100644
--- a/includes/discovery/os/windows.inc.php
+++ b/includes/discovery/os/windows.inc.php
@@ -1,6 +1,6 @@
 <?php
 
-if (starts_with('.1.3.6.1.4.1.311.1.1.3', $sysObjectId)) {
+if (starts_with($sysObjectId, '.1.3.6.1.4.1.311.1.1.3')) {
     $os = 'windows';
 }
 
diff --git a/includes/discovery/os/wxgoos.inc.php b/includes/discovery/os/wxgoos.inc.php
index 569546ac37..10d6d7ebee 100644
--- a/includes/discovery/os/wxgoos.inc.php
+++ b/includes/discovery/os/wxgoos.inc.php
@@ -1,6 +1,6 @@
 <?php
 
-if (str_contains('NETOS 6.0', $sysDescr)) {
+if (str_contains($sysDescr, 'NETOS 6.0')) {
     $os = 'wxgoos';
 }
 
diff --git a/includes/discovery/os/zynos.inc.php b/includes/discovery/os/zynos.inc.php
index 8423797031..71817bd857 100644
--- a/includes/discovery/os/zynos.inc.php
+++ b/includes/discovery/os/zynos.inc.php
@@ -1,5 +1,5 @@
 <?php
 
-if (starts_with('.1.3.6.1.4.1.890', $sysObjectId) && starts_with($sysDescr, array('ES', 'GS'))) {
+if (starts_with($sysObjectId, '.1.3.6.1.4.1.890') && starts_with($sysDescr, array('ES', 'GS'))) {
     $os = 'zynos';
 }
diff --git a/includes/discovery/os/zywall.inc.php b/includes/discovery/os/zywall.inc.php
index 254351a09c..b0bc11534f 100644
--- a/includes/discovery/os/zywall.inc.php
+++ b/includes/discovery/os/zywall.inc.php
@@ -1,6 +1,6 @@
 <?php
 
-if (starts_with('ZyWALL 2X', $sysDescr)) {
+if (starts_with($sysDescr, 'ZyWALL 2X')) {
     $os = 'zywall';
 }
 
diff --git a/includes/discovery/os/zyxelnwa.inc.php b/includes/discovery/os/zyxelnwa.inc.php
index ae2e031641..b535cefb2b 100644
--- a/includes/discovery/os/zyxelnwa.inc.php
+++ b/includes/discovery/os/zyxelnwa.inc.php
@@ -1,5 +1,5 @@
 <?php
 
-if (starts_with('NWA-', $sysDescr)) {
+if (starts_with($sysDescr, 'NWA-')) {
     $os = 'zyxelnwa';
 }