diff --git a/libraries/AP_SerialManager/AP_SerialManager.cpp b/libraries/AP_SerialManager/AP_SerialManager.cpp
index 3aa3407b7c..63a12b3eb4 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.cpp
+++ b/libraries/AP_SerialManager/AP_SerialManager.cpp
@@ -136,7 +136,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 1_PROTOCOL
     // @DisplayName: Telem1 protocol selection
     // @Description: Control what protocol to use on the Telem1 port. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow, 19:RobotisServo, 20:NMEA Output, 21:WindVane, 22:SLCAN, 23:RCIN, 24:MegaSquirt EFI, 25:LTM, 26:RunCam, 27:HottTelem, 28:Scripting, 29:Crossfire VTX, 30:Generator, 31:Winch, 32:MSP, 33:DJI FPV, 34:AirSpeed, 35:ADSB, 36:AHRS, 37:SmartAudio, 38:FETtecOneWire, 39:Torqeedo, 40:AIS, 41:CoDevESC, 42:DisplayPort
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow, 19:RobotisServo, 20:NMEA Output, 21:WindVane, 22:SLCAN, 23:RCIN, 24:MegaSquirt EFI, 25:LTM, 26:RunCam, 27:HottTelem, 28:Scripting, 29:Crossfire VTX, 30:Generator, 31:Winch, 32:MSP, 33:DJI FPV, 34:AirSpeed, 35:ADSB, 36:AHRS, 37:SmartAudio, 38:FETtecOneWire, 39:Torqeedo, 40:AIS, 41:CoDevESC, 42:DisplayPort, 43:MAVLink High Latency
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("1_PROTOCOL",  1, AP_SerialManager, state[1].protocol, SerialProtocol_MAVLink2),
@@ -461,6 +461,7 @@ void AP_SerialManager::init()
                 case SerialProtocol_Console:
                 case SerialProtocol_MAVLink:
                 case SerialProtocol_MAVLink2:
+                case SerialProtocol_MAVLinkHL:
                     uart->begin(map_baudrate(state[i].baud), 
                                          AP_SERIALMANAGER_MAVLINK_BUFSIZE_RX,
                                          AP_SERIALMANAGER_MAVLINK_BUFSIZE_TX);
@@ -676,7 +677,8 @@ AP_SerialManager::SerialProtocol AP_SerialManager::get_mavlink_protocol(mavlink_
     uint8_t chan_idx = (uint8_t)(mav_chan - MAVLINK_COMM_0);
     for (uint8_t i=0; i<SERIALMANAGER_NUM_PORTS; i++) {
         if (state[i].protocol == SerialProtocol_MAVLink ||
-            state[i].protocol == SerialProtocol_MAVLink2) {
+            state[i].protocol == SerialProtocol_MAVLink2 || 
+            state[i].protocol == SerialProtocol_MAVLinkHL) {
             if (instance == chan_idx) {
                 return (SerialProtocol)state[i].protocol.get();
             }
@@ -755,8 +757,8 @@ bool AP_SerialManager::protocol_match(enum SerialProtocol protocol1, enum Serial
     }
 
     // mavlink match
-    if (((protocol1 == SerialProtocol_MAVLink) || (protocol1 == SerialProtocol_MAVLink2)) &&
-        ((protocol2 == SerialProtocol_MAVLink) || (protocol2 == SerialProtocol_MAVLink2))) {
+    if (((protocol1 == SerialProtocol_MAVLink) || (protocol1 == SerialProtocol_MAVLink2) || (protocol1 == SerialProtocol_MAVLinkHL)) &&
+        ((protocol2 == SerialProtocol_MAVLink) || (protocol2 == SerialProtocol_MAVLink2) || (protocol2 == SerialProtocol_MAVLinkHL))) {
         return true;
     }
 
diff --git a/libraries/AP_SerialManager/AP_SerialManager.h b/libraries/AP_SerialManager/AP_SerialManager.h
index c60be5648a..65bc69e363 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.h
+++ b/libraries/AP_SerialManager/AP_SerialManager.h
@@ -169,6 +169,7 @@ public:
         SerialProtocol_AIS = 40,
         SerialProtocol_CoDevESC = 41,
         SerialProtocol_MSP_DisplayPort = 42,
+        SerialProtocol_MAVLinkHL = 43,
         SerialProtocol_NumProtocols                    // must be the last value
     };