diff --git a/includes/definitions/freebsd.yaml b/includes/definitions/freebsd.yaml
index adc2d6ecf1..03d037a543 100644
--- a/includes/definitions/freebsd.yaml
+++ b/includes/definitions/freebsd.yaml
@@ -8,3 +8,5 @@ over:
     - { graph: device_ucd_memory, text: 'Memory Usage' }
 discovery_modules:
     applications: 1
+discovery:
+    - sysDescr: FreeBSD
diff --git a/includes/definitions/linux.yaml b/includes/definitions/linux.yaml
index a72ce0371c..245f198a70 100644
--- a/includes/definitions/linux.yaml
+++ b/includes/definitions/linux.yaml
@@ -31,3 +31,6 @@ register_mibs:
     KNIrxCounter: GANDI-MIB
     KNItxCounter: GANDI-MIB
     KNIdropCounter: GANDI-MIB
+discovery:
+    - sysObjectId: .1.3.6.1.4.1.8072.3.2.10
+    - sysDescr_regex: '/^Linux/'
diff --git a/includes/discovery/os/freebsd.inc.php b/includes/discovery/os/freebsd.inc.php
deleted file mode 100644
index 757c6c0370..0000000000
--- a/includes/discovery/os/freebsd.inc.php
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-// do not move to yaml, this check needs to happen last
-if (str_contains($sysDescr, 'FreeBSD')) {
-    $os = 'freebsd';
-}
diff --git a/includes/discovery/os/linux.inc.php b/includes/discovery/os/linux.inc.php
deleted file mode 100644
index f49e497ac1..0000000000
--- a/includes/discovery/os/linux.inc.php
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-
-// do not move to yaml, this check needs to happen last
-
-if (starts_with($sysDescr, 'Linux') || starts_with($sysObjectId, '.1.3.6.1.4.1.8072.3.2.10')) {
-    $os = 'linux';
-}
diff --git a/includes/discovery/os/airos.inc.php b/includes/discovery/os/ubnt.inc.php
similarity index 100%
rename from includes/discovery/os/airos.inc.php
rename to includes/discovery/os/ubnt.inc.php
diff --git a/includes/functions.php b/includes/functions.php
index f5a3b3ee78..8a84e4f026 100644
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -95,31 +95,24 @@ function getHostOS($device)
 {
     global $config;
 
+    $deferred_os = array(
+        'freebsd',
+        'linux',
+        'ibmtl'  //only has snmpget check
+    );
+
     $sysDescr    = snmp_get($device, "SNMPv2-MIB::sysDescr.0", "-Ovq");
     $sysObjectId = snmp_get($device, "SNMPv2-MIB::sysObjectID.0", "-Ovqn");
 
     d_echo("| $sysDescr | $sysObjectId | \n");
 
     // check yaml files
-    $pattern = $config['install_dir'] . '/includes/definitions/*.yaml';
-    foreach (glob($pattern) as $file) {
-        $os = basename($file, '.yaml');
-        if (isset($config['os'][$os]['os'])) {
-            $tmp = $config['os'][$os];
-        } else {
-            $tmp = Symfony\Component\Yaml\Yaml::parse(
-                file_get_contents($file)
-            );
-            // pull in user overrides
-            if (isset($config['os'][$os])) {
-                $tmp = array_replace_recursive($tmp, $config['os'][$os]);
-            }
-        }
-        if (isset($tmp['discovery']) && is_array($tmp['discovery'])) {
-            foreach ($tmp['discovery'] as $item) {
-                // check each item individually, if all the conditions in that item are true, we have a match
+    $os_defs = Config::get('os');
+    foreach ($os_defs as $os => $def) {
+        if (isset($def['discovery'])  && !in_array($os, $deferred_os)) {
+            foreach ($def['discovery'] as $item) {
                 if (checkDiscovery($device, $item, $sysObjectId, $sysDescr)) {
-                    return $tmp['os'];
+                    return $os;
                 }
             }
         }
@@ -135,6 +128,17 @@ function getHostOS($device)
         }
     }
 
+    // check deferred os
+    foreach ($deferred_os as $os) {
+        if (isset($os_defs[$os]['discovery'])) {
+            foreach ($os_defs[$os]['discovery'] as $item) {
+                if (checkDiscovery($device, $item, $sysObjectId, $sysDescr)) {
+                    return $os;
+                }
+            }
+        }
+    }
+
     return 'generic';
 }