Add SERIALSHOT ESC protocol

_locales/en/messages.json

@@ -2956,6 +2956,9 @@
     "escProtocolNotAdvised": {
         "message": "This ESC protocol is not advised, use it at your own risk"
     },
+    "escProtocolExperimental": {
+        "message": "Experimental ESC protocol, use at your own risk"
+    },
     "looptimeNotAdvised": {
         "message": "PID loop might be not stable if GPS is in use"
     },

js/fc.js

@@ -921,6 +921,14 @@ var FC = {
                 rates: {
                     16000: "16kHz"
                 }
+            },
+            9: {
+                name: "SERIALSHOT",
+                message: "escProtocolExperimental",
+                defaultRate: 4000,
+                rates: {
+                    4000: "4kHz"
+                }
             }
         };
     },

tabs/configuration.js

@@ -459,7 +459,7 @@ TABS.configuration.initialize = function (callback, scrollPosition) {
             }
 
             if (ADVANCED_CONFIG.motorPwmProtocol >= 5) {
-                //DSHOT protocols, simplify UI
+                //DSHOT/SERIALSHOT protocols, simplify UI
                 $('.hide-for-shot').addClass('is-hidden');
             } else {
                 $('.hide-for-shot').removeClass('is-hidden');