diff --git a/libraries/AP_IOMCU/AP_IOMCU.cpp b/libraries/AP_IOMCU/AP_IOMCU.cpp
index d89d7bc2b2..9ee672e1ed 100644
--- a/libraries/AP_IOMCU/AP_IOMCU.cpp
+++ b/libraries/AP_IOMCU/AP_IOMCU.cpp
@@ -19,6 +19,7 @@
 #include <AP_RCProtocol/AP_RCProtocol.h>
 #include <AP_InternalError/AP_InternalError.h>
 #include <AP_Logger/AP_Logger.h>
+#include <AP_RCProtocol/AP_RCProtocol.h>
 
 extern const AP_HAL::HAL &hal;
 
@@ -247,6 +248,8 @@ void AP_IOMCU::thread_main(void)
                 pwm_out.failsafe_pwm_sent = set;
             }
         }
+
+        send_rc_protocols();
     }
     done_shutdown = true;
 }
@@ -769,6 +772,18 @@ void AP_IOMCU::update_safety_options(void)
     }
 }
 
+// update enabled RC protocols mask
+void AP_IOMCU::send_rc_protocols()
+{
+    const uint32_t v = rc().enabled_protocols();
+    if (last_rc_protocols == v) {
+        return;
+    }
+    if (write_registers(PAGE_SETUP, PAGE_REG_SETUP_RC_PROTOCOLS, 2, (uint16_t *)&v)) {
+        last_rc_protocols = v;
+    }
+}
+
 /*
   check ROMFS firmware against CRC on IOMCU, and if incorrect then upload new firmware
  */
@@ -1023,6 +1038,7 @@ void AP_IOMCU::check_iomcu_reset(void)
     }
     trigger_event(IOEVENT_SET_RATES);
     trigger_event(IOEVENT_SET_DEFAULT_RATE);
+    last_rc_protocols = 0;
 }
 
 
diff --git a/libraries/AP_IOMCU/AP_IOMCU.h b/libraries/AP_IOMCU/AP_IOMCU.h
index 57a922c11c..69f02cce39 100644
--- a/libraries/AP_IOMCU/AP_IOMCU.h
+++ b/libraries/AP_IOMCU/AP_IOMCU.h
@@ -161,6 +161,7 @@ private:
     void discard_input(void);
     void event_failed(uint8_t event);
     void update_safety_options(void);
+    void send_rc_protocols(void);
 
     // CONFIG page
     struct page_config config;
@@ -223,6 +224,7 @@ private:
     uint32_t last_iocmu_timestamp_ms;
     uint32_t read_status_errors;
     uint32_t read_status_ok;
+    uint32_t last_rc_protocols;
 
     // firmware upload
     const char *fw_name = "io_firmware.bin";
diff --git a/libraries/AP_IOMCU/iofirmware/iofirmware.cpp b/libraries/AP_IOMCU/iofirmware/iofirmware.cpp
index 9b407ace30..228825e7d3 100644
--- a/libraries/AP_IOMCU/iofirmware/iofirmware.cpp
+++ b/libraries/AP_IOMCU/iofirmware/iofirmware.cpp
@@ -558,6 +558,15 @@ bool AP_IOMCU_FW::handle_code_write()
             }
             break;
 
+        case PAGE_REG_SETUP_RC_PROTOCOLS: {
+            if (rx_io_packet.count == 2) {
+                uint32_t v;
+                memcpy(&v, &rx_io_packet.regs[0], 4);
+                AP::RC().set_rc_protocols(v);
+            }
+            break;
+        }
+
         default:
             break;
         }
diff --git a/libraries/AP_IOMCU/iofirmware/ioprotocol.h b/libraries/AP_IOMCU/iofirmware/ioprotocol.h
index 04d9fcce9e..4532f4369b 100644
--- a/libraries/AP_IOMCU/iofirmware/ioprotocol.h
+++ b/libraries/AP_IOMCU/iofirmware/ioprotocol.h
@@ -83,6 +83,7 @@ enum iopage {
 #define PAGE_REG_SETUP_IGNORE_SAFETY 20 /* bitmask of surfaces to ignore the safety status */
 #define PAGE_REG_SETUP_HEATER_DUTY_CYCLE 21
 #define PAGE_REG_SETUP_DSM_BIND     22
+#define PAGE_REG_SETUP_RC_PROTOCOLS 23 // uses 2 slots, 23 and 24
 
 // config page registers
 #define PAGE_CONFIG_PROTOCOL_VERSION  0