diff --git a/files/usr/local/bin/mgr/rssi_monitor_ath10k.lua b/files/usr/local/bin/mgr/rssi_monitor_ath10k.lua
index cf701149..eb9804fe 100644
--- a/files/usr/local/bin/mgr/rssi_monitor_ath10k.lua
+++ b/files/usr/local/bin/mgr/rssi_monitor_ath10k.lua
@@ -45,7 +45,7 @@ function rssi_monitor_10k()
 
         -- ath10k only
         local phy = iwinfo.nl80211.phyname(wifiiface)
-        if not nixio.fs.stat("/sys/kernel/debug/ieee80211/" .. phy .. "/ath10k") then
+        if not phy or not nixio.fs.stat("/sys/kernel/debug/ieee80211/" .. phy .. "/ath10k") then
             exit_app()
             return
         end
diff --git a/files/usr/local/bin/mgr/rssi_monitor_ath9k.lua b/files/usr/local/bin/mgr/rssi_monitor_ath9k.lua
index ae505008..4e8e75f1 100644
--- a/files/usr/local/bin/mgr/rssi_monitor_ath9k.lua
+++ b/files/usr/local/bin/mgr/rssi_monitor_ath9k.lua
@@ -48,7 +48,7 @@ function rssi_monitor_9k()
         phy = iwinfo.nl80211.phyname(wifiiface)
     
         -- Supports ath9k
-        if not nixio.fs.stat("/sys/kernel/debug/ieee80211/" .. phy .. "/ath9k") then
+        if not phy or not nixio.fs.stat("/sys/kernel/debug/ieee80211/" .. phy .. "/ath9k") then
             exit_app()
             return
         end