diff --git a/libraries/AP_RCProtocol/AP_RCProtocol.cpp b/libraries/AP_RCProtocol/AP_RCProtocol.cpp
index 1b73608a2d..bc07ce3493 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol.cpp
+++ b/libraries/AP_RCProtocol/AP_RCProtocol.cpp
@@ -45,7 +45,9 @@ void AP_RCProtocol::init()
 #endif
     backend[AP_RCProtocol::DSM] = new AP_RCProtocol_DSM(*this);
     backend[AP_RCProtocol::SUMD] = new AP_RCProtocol_SUMD(*this);
+#if AP_RCPROTOCOL_SRXL_ENABLED
     backend[AP_RCProtocol::SRXL] = new AP_RCProtocol_SRXL(*this);
+#endif
 #ifndef IOMCU_FW
     backend[AP_RCProtocol::SBUS_NI] = new AP_RCProtocol_SBUS(*this, false, 100000);
     backend[AP_RCProtocol::SRXL2] = new AP_RCProtocol_SRXL2(*this);
@@ -420,8 +422,10 @@ const char *AP_RCProtocol::protocol_name_from_protocol(rcprotocol_t protocol)
         return "DSM";
     case SUMD:
         return "SUMD";
+#if AP_RCPROTOCOL_SRXL_ENABLED
     case SRXL:
         return "SRXL";
+#endif
     case SRXL2:
         return "SRXL2";
     case CRSF:
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol.h b/libraries/AP_RCProtocol/AP_RCProtocol.h
index 2caf8a1cda..9d17e96739 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol.h
+++ b/libraries/AP_RCProtocol/AP_RCProtocol.h
@@ -47,7 +47,9 @@ public:
         SBUS_NI    =  3,
         DSM        =  4,
         SUMD       =  5,
+#if AP_RCPROTOCOL_SRXL_ENABLED
         SRXL       =  6,
+#endif
         SRXL2      =  7,
         CRSF       =  8,
         ST24       =  9,
@@ -105,7 +107,9 @@ public:
             return true;
         case IBUS:
         case SUMD:
+#if AP_RCPROTOCOL_SRXL_ENABLED
         case SRXL:
+#endif
         case SRXL2:
         case ST24:
         case NONE:
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.cpp b/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.cpp
index 8e05bb6f4e..934f26c88d 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.cpp
+++ b/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.cpp
@@ -20,6 +20,10 @@
    - 2016.10.23: SRXL variant V1 sucessfully (Testbench and Pixhawk/MissionPlanner) tested with RX-9-DR M-LINK (SW v1.26)
  */
 
+#include "AP_RCProtocol_config.h"
+
+#if AP_RCPROTOCOL_SRXL_ENABLED
+
 #include "AP_RCProtocol_SRXL.h"
 #include <AP_Math/crc.h>
 #include <AP_Math/AP_Math.h>
@@ -281,3 +285,5 @@ void AP_RCProtocol_SRXL::process_byte(uint8_t byte, uint32_t baudrate)
     }
     _process_byte(AP_HAL::micros(), byte);
 }
+
+#endif  // AP_RCPROTOCOL_SRXL_ENABLED
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.h b/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.h
index eb1429949e..504f061cb1 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.h
+++ b/libraries/AP_RCProtocol/AP_RCProtocol_SRXL.h
@@ -17,11 +17,17 @@
 
 #pragma once
 
+#include "AP_RCProtocol_config.h"
+
+// this define is out here because SRXL2 uses it - probably incorrectly
+#define SRXL_MAX_CHANNELS 20U           /* Maximum number of channels from srxl datastream  */
+
+#if AP_RCPROTOCOL_SRXL_ENABLED
+
 #include "AP_RCProtocol.h"
 #include "SoftSerial.h"
 
 #define SRXL_MIN_FRAMESPACE_US 8000U    /* Minumum space between srxl frames in us (applies to all variants)  */
-#define SRXL_MAX_CHANNELS 20U           /* Maximum number of channels from srxl datastream  */
 
 /* Variant specific SRXL datastream characteristics */
 /* Framelength in byte */
@@ -64,3 +70,5 @@ private:
 
     SoftSerial ss{115200, SoftSerial::SERIAL_CONFIG_8N1};
 };
+
+#endif  // AP_RCPROTOCOL_SRXL_ENABLED
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_config.h b/libraries/AP_RCProtocol/AP_RCProtocol_config.h
index d9361e58ff..f489879bce 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol_config.h
+++ b/libraries/AP_RCProtocol/AP_RCProtocol_config.h
@@ -1,10 +1,19 @@
 #pragma once
 
+#include <AP_HAL/AP_HAL_Boards.h>
 #include <AP_Frsky_Telem/AP_Frsky_config.h>
 
+#ifndef AP_RCPROTOCOL_BACKEND_DEFAULT_ENABLED
+#define AP_RCPROTOCOL_BACKEND_DEFAULT_ENABLED 1
+#endif
+
 #ifndef AP_RCPROTOCOL_FPORT_ENABLED
-#define AP_RCPROTOCOL_FPORT_ENABLED AP_FRSKY_SPORT_TELEM_ENABLED
+#define AP_RCPROTOCOL_FPORT_ENABLED AP_RCPROTOCOL_BACKEND_DEFAULT_ENABLED && AP_FRSKY_SPORT_TELEM_ENABLED
 #endif
 #ifndef AP_RCPROTOCOL_FPORT2_ENABLED
-#define AP_RCPROTOCOL_FPORT2_ENABLED AP_FRSKY_SPORT_TELEM_ENABLED
+#define AP_RCPROTOCOL_FPORT2_ENABLED AP_RCPROTOCOL_BACKEND_DEFAULT_ENABLED && AP_FRSKY_SPORT_TELEM_ENABLED
+#endif
+
+#ifndef AP_RCPROTOCOL_SRXL_ENABLED
+#define AP_RCPROTOCOL_SRXL_ENABLED AP_RCPROTOCOL_BACKEND_DEFAULT_ENABLED
 #endif