diff --git a/Troubleshooting-Guide.md b/Troubleshooting-Guide.md
index 71ff597..e9be7e2 100644
--- a/Troubleshooting-Guide.md
+++ b/Troubleshooting-Guide.md
@@ -147,9 +147,53 @@ Other paths to look in, depending on your hardware.
 /etc/dhcpd/dhcpd-zzz-ctrld.conf
 /etc/dnsmasq.d/dnsmasq-zzz-ctrld.conf
 /tmp/dnsmasq.d/ctrld.conf
+/home/pi/.firewalla/config/dnsmasq_local/ctrld
 ```
 
-If this config doesn't exist, or has a different IP + port, that's a problem. Try restarting the `ctrld` service and see if the issue goes away. 
+If this config doesn't exist, or has a different IP + port, that's a problem. Try restarting the `ctrld` service and see if the issue goes away.
+
+On Merlin routers, you may want to check if `/jffs/scripts/dnsmasq.postconf` exists and contains following content:
+
+```
+root@RT-AX56U-4F98:/jffs/controld# cat /jffs/scripts/dnsmasq.postconf 
+# GENERATED BY ctrld - DO NOT MODIFY
+
+#!/bin/sh
+
+config_file="$1"
+. /usr/sbin/helper.sh
+
+pid=$(cat /tmp/ctrld.pid 2>/dev/null)
+if [ -n "$pid" ] && [ -f "/proc/${pid}/cmdline" ]; then
+  pc_delete "servers-file" "$config_file"           # no WAN DNS settings
+  pc_append "no-resolv" "$config_file"              # do not read /etc/resolv.conf
+  # use ctrld as upstream
+  pc_delete "server=" "$config_file"
+  pc_append "server=127.0.0.1#5354" "$config_file"
+  pc_append "add-mac" "$config_file"                # add client mac
+  pc_delete "dnssec" "$config_file"                 # disable DNSSEC
+  pc_delete "trust-anchor=" "$config_file"          # disable DNSSEC
+	
+  # For John fork
+  pc_delete "resolv-file" "$config_file"            # no WAN DNS settings
+
+  # Change /etc/resolv.conf, which may be changed by WAN DNS setup
+  pc_delete "nameserver" /etc/resolv.conf
+  pc_append "nameserver 127.0.0.1" /etc/resolv.conf
+
+  exit 0
+fi
+
+
+
+# GENERATED BY ctrld - EOF
+```
+
+On routers with `nvram` utility (ddwrt, freshtomato), you may want to check if the config was set correctly in router memory:
+
+```
+nvram show | grep dnsmasq_
+```
 
 ## Debug launch
 If the service doesn't start, or hangs, try running it in debug mode and collect a log. This can be done using the following command: