i dont think the default mode is required

mission/devices/SyrlinksHandler.cpp

@@ -25,7 +25,7 @@ void SyrlinksHandler::doStartUp() {
   }
   if (internalState == InternalState::ENABLE_TEMPERATURE_PROTECTION) {
     if (commandExecuted) {
-      // Got to normal mode immediately.
+      // Got to normal mode immediately and disable transmitter on startup.
       setMode(_MODE_TO_NORMAL);
       internalState = InternalState::IDLE;
       commandExecuted = false;
@@ -740,6 +740,18 @@ void SyrlinksHandler::doTransition(Mode_t modeFrom, Submode_t subModeFrom) {
     }
     return false;
   };
+  auto txStandbyHandler = [&]() {
+    if (internalState == InternalState::IDLE) {
+      internalState = InternalState::SET_TX_STANDBY;
+      commandExecuted = false;
+    }
+    if (internalState == InternalState::SET_TX_STANDBY) {
+      if (commandExecuted) {
+        commandDone();
+        return;
+      }
+    }
+  };
   if (tgtMode == HasModesIF::MODE_ON or tgtMode == DeviceHandlerIF::MODE_NORMAL) {
     switch (getSubmode()) {
       case (syrlinks::Submode::RX_AND_TX_DEFAULT_DATARATE): {
@@ -768,17 +780,8 @@ void SyrlinksHandler::doTransition(Mode_t modeFrom, Submode_t subModeFrom) {
         break;
       }
       case (syrlinks::Submode::RX_ONLY): {
-        if (internalState == InternalState::IDLE) {
-          internalState = InternalState::SET_TX_STANDBY;
-          commandExecuted = false;
-        }
-        if (internalState == InternalState::SET_TX_STANDBY) {
-          if (commandExecuted) {
-            commandDone();
-            return;
-          }
-        }
-        break;
+        txStandbyHandler();
+        return;
       }
       case (syrlinks::Submode::RX_AND_TX_CW): {
         if (internalState == InternalState::IDLE) {

mission/devices/devicedefinitions/SyrlinksDefinitions.h

@@ -9,7 +9,6 @@ namespace syrlinks {
 enum class ParameterId : uint8_t { DATARATE = 0 };
 
 enum Submode {
-  DEFAULT,
   RX_ONLY,
   RX_AND_TX_DEFAULT_DATARATE,
   RX_AND_TX_LOW_DATARATE,