diff --git a/libraries/AP_Scripting/applets/RockBlock.lua b/libraries/AP_Scripting/applets/RockBlock.lua
index 2c5e175b1be1c0..02df3e4fcf59ea 100644
--- a/libraries/AP_Scripting/applets/RockBlock.lua
+++ b/libraries/AP_Scripting/applets/RockBlock.lua
@@ -10,7 +10,7 @@ Usage:
 Use the MAVLink High Latency Control ("link hl on|off" in MAVProxy) to control
 whether to send or not (or use "force_hl_enable")
 Use the RCK_DEBUG param to view debugging statustexts at the GCS
-Use the RCK_FORCEHL param to force-enable high latency mode, instead of enabling from GCS
+Use the RCK_FORCEHL param to control the mode of operation: 0=Disabled, 1=Enabled, 2=Enabled on 5000ms telemetry loss
 
 Caveats:
 This will *only* send HIGH_LATENCY2 packets via the SBD modem. No heartbeats,
@@ -39,6 +39,9 @@ end
 port:begin(19200)
 port:set_flow_control(0)
 
+-- number of millsec that GCS telemetry has been lost for
+local link_lost_for = 0
+
 -- bind a parameter to a variable
 function bind_param(name)
     local p = Parameter()
@@ -58,7 +61,7 @@ assert(param:add_table(PARAM_TABLE_KEY, PARAM_TABLE_PREFIX, 4), 'could not add p
   // @Param: RCK_FORCEHL
   // @DisplayName: Force enable High Latency mode
   // @Description: Automatically enables High Latency mode if not already enabled
-  // @Values: 0:Disabled,1:Enabled
+  // @Values: 0:Disabled,1:Enabled,2:Enabled on 5000ms telemetry loss
   // @User: Standard
 --]]
 RCK_FORCEHL     = bind_add_param('FORCEHL', 1, 0)
@@ -91,6 +94,13 @@ RCK_DEBUG     = bind_add_param('DEBUG', 3, 0)
 --]]
 RCK_ENABLE     = bind_add_param('ENABLE', 4, 1)
 
+--[[
+Returns true if the value is NaN, false otherwise
+--]]
+local function isNaN (x)
+    return (x ~= x)
+  end
+
 --[[
 Lua Object for decoding and encoding MAVLink (V1 only) messages
 --]]
@@ -102,7 +112,8 @@ local function MAVLinkProcessor()
         COMMAND_INT = 75,
         HIGH_LATENCY2 = 235,
         MISSION_ITEM_INT = 73,
-        SET_MODE = 11
+        SET_MODE = 11,
+        MISSION_SET_CURRENT = 41
     }
 
     -- private fields
@@ -121,6 +132,7 @@ local function MAVLinkProcessor()
     _crc_extra[235] = 0xb3
     _crc_extra[73] = 0x26
     _crc_extra[11] = 0x59
+    _crc_extra[41] = 0x1c
     
     local _messages = {}
     _messages[75] = { -- COMMAND_INT
@@ -156,6 +168,9 @@ local function MAVLinkProcessor()
     _messages[11] = { -- SET_MODE
         { "custom_mode", "<I4" }, { "target_system", "<B" }, { "base_mode", "<B" },
     }
+    _messages[41] = { -- MISSION_SET_CURRENT
+        { "seq", "<I2" }, { "target_system", "<B" }, { "target_component", "<B" },
+    }
     function self.getSeqID() return _txseqid end
 
     function self.generateCRC(buffer)
@@ -269,53 +284,59 @@ local function MAVLinkProcessor()
                 end
             elseif _mavresult.msgid == self.SET_MODE then
                 vehicle:set_mode(_mavresult.custom_mode)
-            elseif _mavresult.msgid == self.COMMAND_LONG or _mavresult.msgid ==
-                self.COMMAND_INT then
-                if _mavresult.command == 400 then -- MAV_CMD_COMPONENT_ARM_DISARM
-                    if _mavresult.param1 == 1 then
-                        arming:arm()
-                    elseif _mavresult.param1 == 0 then
-                        arming:disarm()
-                    end
-                elseif _mavresult.command == 176 then -- MAV_CMD_DO_SET_MODE
-                    vehicle:set_mode(_mavresult.param2)
-                elseif _mavresult.command == 20 then -- MAV_CMD_NAV_RETURN_TO_LAUNCH (Mode RTL) may vary depending on frame
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(6)
-                    elseif FWVersion:type() == 3 then -- plane
-                        vehicle:set_mode(11)
-                    elseif FWVersion:type() == 1 then -- rover
-                        vehicle:set_mode(11)
-                    end
-                elseif _mavresult.command == 21 then -- MAV_CMD_NAV_LAND (Mode LAND) may vary depending on frame
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(9)
-                    elseif FWVersion:type() == 12 then -- blimp
-                        vehicle:set_mode(0)
-                    end
-                elseif _mavresult.command == 22 then -- MAV_CMD_NAV_TAKEOFF
-                    vehicle:start_takeoff(_mavresult.param7)
-                elseif _mavresult.command == 84 then -- MAV_CMD_NAV_VTOL_TAKEOFF
-                    vehicle:start_takeoff(_mavresult.param7)
-                elseif _mavresult.command == 85 then -- MAV_CMD_NAV_VTOL_LAND (Mode QLAND)
-                    vehicle:set_mode(20)
-                elseif _mavresult.command == 300 then -- MAV_CMD_MISSION_START --mode auto and then start mission
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(3)
-                    elseif FWVersion:type() == 3 then -- plane
-                        vehicle:set_mode(10)
-                    elseif FWVersion:type() == 1 then -- rover
-                        vehicle:set_mode(10)
-                    elseif FWVersion:type() == 7 then -- sub
-                        vehicle:set_mode(3)
-                    end
-                elseif _mavresult.command == 2600 then -- MAV_CMD_CONTROL_HIGH_LATENCY
-                    if _mavresult.param1 == 1 then
-                        gcs:enable_high_latency_connections(true)
-                    else
-                        gcs:enable_high_latency_connections(false)
-                    end
+            elseif _mavresult.msgid == self.COMMAND_LONG then
+                --- need to do a little conversion here. Taken from convert_COMMAND_LONG_to_COMMAND_INT()
+                local command_long_stores_location = 0
+                if (_mavresult.command == 179 or       -- MAV_CMD_DO_SET_HOME
+                    _mavresult.command ==  201 or      -- MAV_CMD_DO_SET_ROI
+                    _mavresult.command ==  195 or      -- MAV_CMD_DO_SET_ROI_LOCATION
+                    _mavresult.command ==  192 or      -- MAV_CMD_DO_REPOSITION
+                    _mavresult.command ==  43003) then -- MAV_CMD_EXTERNAL_POSITION_ESTIMATE
+                    command_long_stores_location = 1
+                end
+                local int_frame = 0       -- MAV_FRAME_GLOBAL
+                if (_mavresult.command ==  195) then       -- MAV_CMD_DO_SET_ROI_LOCATION
+                    int_frame = 3         -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                elseif (_mavresult.command ==  179) then   -- MAV_CMD_DO_SET_HOME
+                    int_frame = 0        -- MAV_FRAME_GLOBAL
+                elseif (_mavresult.command ==  201) then   -- MAV_CMD_DO_SET_ROI
+                    int_frame = 3        -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                elseif (_mavresult.command ==  42006) then   -- MAV_CMD_FIXED_MAG_CAL_YAW
+                    int_frame = 3        -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                end
+                local int_x = _mavresult.param5
+                local int_y = _mavresult.param6
+                if isNaN(int_x) then
+                    int_x = 0
+                end
+                if isNaN(int_y) then
+                    int_y = 0
+                end
+                if command_long_stores_location == 1 then
+                    int_x = 1E7 * int_x
+                    int_y = 1E7 * int_y
                 end
+                gcs:run_command_int(_mavresult.command, { p1 = _mavresult.param1,
+                                                          p2 = _mavresult.param2,
+                                                          p3 = _mavresult.param3,
+                                                          p4 = _mavresult.param4,
+                                                          x = int_x,
+                                                          y = int_y,
+                                                          z = _mavresult.param7,
+                                                          int_frame = 0,
+                                                          current = 0,
+                                                          autocontinue = 0 })
+            elseif _mavresult.msgid == self.COMMAND_INT then
+                gcs:run_command_int(_mavresult.command, { p1 = _mavresult.param1,
+                                                          p2 = _mavresult.param2,
+                                                          p3 = _mavresult.param3,
+                                                          p4 = _mavresult.param4,
+                                                          x = _mavresult.x,
+                                                          y = _mavresult.y,
+                                                          z = _mavresult.z,
+                                                          frame = _mavresult.frame })
+            elseif _mavresult.msgid == self.MISSION_SET_CURRENT then
+                mission:set_current_cmd(_mavresult.seq)
             end
             _mavbuffer = ""
             return true
@@ -719,6 +740,22 @@ function HLSatcom()
         gcs:send_text(3, "Rockblock: Trying to detect modem")
         rockblock.checkmodem()
     end
+
+    --- check if GCS telemetry has been lost for 5000 millisec (if param enabled)
+    if RCK_FORCEHL:get() == 2 then
+        if last_seen == gcs:last_seen() then
+            link_lost_for = link_lost_for + 100
+        else
+            -- There has been a new heartbeat, update last_seen and reset link_lost_for
+            last_seen = gcs:last_seen()
+            link_lost_for = 0
+        end
+        if link_lost_for > 5000 and not gcs:get_high_latency_status() then
+            gcs:enable_high_latency_connections(true)
+        elseif link_lost_for < 5000 and gcs:get_high_latency_status() then
+            gcs:enable_high_latency_connections(false)
+        end
+    end
     
     -- send HL2 packet every 30 sec, if not aleady in a mailbox check
     if rockblock.modem_detected and gcs:get_high_latency_status() and
diff --git a/libraries/AP_Scripting/applets/RockBlock.md b/libraries/AP_Scripting/applets/RockBlock.md
index edd89643da929f..ab6f0f0f395534 100644
--- a/libraries/AP_Scripting/applets/RockBlock.md
+++ b/libraries/AP_Scripting/applets/RockBlock.md
@@ -26,7 +26,10 @@ The script adds the following parameters:
 
 ## RCK_FORCEHL
 
-Automatically enables High Latency mode if not already enabled
+Mode of operation:
+- 0 = start disabled, can be enabled via MAV_CMD_CONTROL_HIGH_LATENCY
+- 1 = start enabled, can be disabled via MAV_CMD_CONTROL_HIGH_LATENCY
+- 2 = enabled on loss of telemetry (GCS) link for 5 seconds
 
 ## RCK_PERIOD
 
diff --git a/libraries/AP_Scripting/examples/MAVLinkHL.lua b/libraries/AP_Scripting/examples/MAVLinkHL.lua
index 21cc968a63ec6a..ec43460ab58590 100644
--- a/libraries/AP_Scripting/examples/MAVLinkHL.lua
+++ b/libraries/AP_Scripting/examples/MAVLinkHL.lua
@@ -5,9 +5,13 @@ This script requires 1 serial port:
 A "Script" serial port to connect directly to the GCS
 
 Usage:
+Use the "hl_mode" variable to control the behaviour of the script:
+0 = start enabled, can be disabled via MAV_CMD_CONTROL_HIGH_LATENCY
+1 = enabled on loss of telemetry link for 5 seconds (default)
+2 = start disabled, can be enabled via MAV_CMD_CONTROL_HIGH_LATENCY
+
 Use the MAVLink High Latency Control ("link hl on|off" in MAVProxy) to control
 whether to send or not
-The script will, however, automatically enable MAVLink High Latency Control upon start
 
 Caveats:
 -This will send HIGH_LATENCY2 packets in place of HEARTBEAT packets
@@ -34,8 +38,20 @@ port:set_flow_control(0)
 
 local time_last_tx = millis():tofloat() * 0.001
 
+local hl_mode = 0
+local link_lost_for = 0
+
 -- enable high latency mode from here, instead of having to enable from GCS
-gcs:enable_high_latency_connections(true)
+if hl_mode == 0 then
+    gcs:enable_high_latency_connections(true)
+end
+
+--[[
+Returns true if the value is NaN, false otherwise
+--]]
+local function isNaN (x)
+    return (x ~= x)
+  end
 
 --[[
 Lua Object for decoding and encoding MAVLink (V1 only) messages
@@ -48,7 +64,8 @@ local function MAVLinkProcessor()
         COMMAND_INT = 75,
         HIGH_LATENCY2 = 235,
         MISSION_ITEM_INT = 73,
-        SET_MODE = 11
+        SET_MODE = 11,
+        MISSION_SET_CURRENT = 41
     }
 
     -- private fields
@@ -67,6 +84,7 @@ local function MAVLinkProcessor()
     _crc_extra[235] = 0xb3
     _crc_extra[73] = 0x26
     _crc_extra[11] = 0x59
+    _crc_extra[41] = 0x1c
 
     local _messages = {}
     _messages[75] = { -- COMMAND_INT
@@ -102,6 +120,9 @@ local function MAVLinkProcessor()
     _messages[11] = { -- SET_MODE
         { "custom_mode", "<I4" }, { "target_system", "<B" }, { "base_mode", "<B" },
     }
+    _messages[41] = { -- MISSION_SET_CURRENT
+        { "seq", "<I2" }, { "target_system", "<B" }, { "target_component", "<B" },
+    }
     function self.getSeqID() return _txseqid end
 
     function self.generateCRC(buffer)
@@ -216,53 +237,59 @@ local function MAVLinkProcessor()
                 end
             elseif _mavresult.msgid == self.SET_MODE then
                 vehicle:set_mode(_mavresult.custom_mode)
-            elseif _mavresult.msgid == self.COMMAND_LONG or _mavresult.msgid ==
-                self.COMMAND_INT then
-                if _mavresult.command == 400 then -- MAV_CMD_COMPONENT_ARM_DISARM
-                    if _mavresult.param1 == 1 then
-                        arming:arm()
-                    elseif _mavresult.param1 == 0 then
-                        arming:disarm()
-                    end
-                elseif _mavresult.command == 176 then -- MAV_CMD_DO_SET_MODE
-                    vehicle:set_mode(_mavresult.param2)
-                elseif _mavresult.command == 20 then -- MAV_CMD_NAV_RETURN_TO_LAUNCH (Mode RTL) may vary depending on frame
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(6)
-                    elseif FWVersion:type() == 3 then -- plane
-                        vehicle:set_mode(11)
-                    elseif FWVersion:type() == 1 then -- rover
-                        vehicle:set_mode(11)
-                    end
-                elseif _mavresult.command == 21 then -- MAV_CMD_NAV_LAND (Mode LAND) may vary depending on frame
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(9)
-                    elseif FWVersion:type() == 12 then -- blimp
-                        vehicle:set_mode(0)
-                    end
-                elseif _mavresult.command == 22 then -- MAV_CMD_NAV_TAKEOFF
-                    vehicle:start_takeoff(_mavresult.param7)
-                elseif _mavresult.command == 84 then -- MAV_CMD_NAV_VTOL_TAKEOFF
-                    vehicle:start_takeoff(_mavresult.param7)
-                elseif _mavresult.command == 85 then -- MAV_CMD_NAV_VTOL_LAND (Mode QLAND)
-                    vehicle:set_mode(20)
-                elseif _mavresult.command == 300 then -- MAV_CMD_MISSION_START --mode auto and then start mission
-                    if FWVersion:type() == 2 then -- copter
-                        vehicle:set_mode(3)
-                    elseif FWVersion:type() == 3 then -- plane
-                        vehicle:set_mode(10)
-                    elseif FWVersion:type() == 1 then -- rover
-                        vehicle:set_mode(10)
-                    elseif FWVersion:type() == 7 then -- sub
-                        vehicle:set_mode(3)
-                    end
-                elseif _mavresult.command == 2600 then -- MAV_CMD_CONTROL_HIGH_LATENCY
-                    if _mavresult.param1 == 1 then
-                        gcs:enable_high_latency_connections(true)
-                    else
-                        gcs:enable_high_latency_connections(false)
-                    end
+            elseif _mavresult.msgid == self.COMMAND_LONG then
+                --- need to do a little conversion here. Taken from convert_COMMAND_LONG_to_COMMAND_INT()
+                local command_long_stores_location = 0
+                if (_mavresult.command == 179 or       -- MAV_CMD_DO_SET_HOME
+                    _mavresult.command ==  201 or      -- MAV_CMD_DO_SET_ROI
+                    _mavresult.command ==  195 or      -- MAV_CMD_DO_SET_ROI_LOCATION
+                    _mavresult.command ==  192 or      -- MAV_CMD_DO_REPOSITION
+                    _mavresult.command ==  43003) then -- MAV_CMD_EXTERNAL_POSITION_ESTIMATE
+                    command_long_stores_location = 1
+                end
+                local int_frame = 0       -- MAV_FRAME_GLOBAL
+                if (_mavresult.command ==  195) then       -- MAV_CMD_DO_SET_ROI_LOCATION
+                    int_frame = 3         -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                elseif (_mavresult.command ==  179) then   -- MAV_CMD_DO_SET_HOME
+                    int_frame = 0        -- MAV_FRAME_GLOBAL
+                elseif (_mavresult.command ==  201) then   -- MAV_CMD_DO_SET_ROI
+                    int_frame = 3        -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                elseif (_mavresult.command ==  42006) then   -- MAV_CMD_FIXED_MAG_CAL_YAW
+                    int_frame = 3        -- MAV_FRAME_GLOBAL_RELATIVE_ALT
+                end
+                local int_x = _mavresult.param5
+                local int_y = _mavresult.param6
+                if isNaN(int_x) then
+                    int_x = 0
+                end
+                if isNaN(int_y) then
+                    int_y = 0
+                end
+                if command_long_stores_location == 1 then
+                    int_x = 1E7 * int_x
+                    int_y = 1E7 * int_y
                 end
+                gcs:run_command_int(_mavresult.command, { p1 = _mavresult.param1,
+                                                          p2 = _mavresult.param2,
+                                                          p3 = _mavresult.param3,
+                                                          p4 = _mavresult.param4,
+                                                          x = int_x,
+                                                          y = int_y,
+                                                          z = _mavresult.param7,
+                                                          int_frame = 0,
+                                                          current = 0,
+                                                          autocontinue = 0 })
+            elseif _mavresult.msgid == self.COMMAND_INT then
+                gcs:run_command_int(_mavresult.command, { p1 = _mavresult.param1,
+                                                          p2 = _mavresult.param2,
+                                                          p3 = _mavresult.param3,
+                                                          p4 = _mavresult.param4,
+                                                          x = _mavresult.x,
+                                                          y = _mavresult.y,
+                                                          z = _mavresult.z,
+                                                          frame = _mavresult.frame })
+            elseif _mavresult.msgid == self.MISSION_SET_CURRENT then
+                mission:set_current_cmd(_mavresult.seq)
             end
             _mavbuffer = ""
             return true
@@ -379,6 +406,22 @@ function HLSatcom()
         if mavlink.parseMAVLink(byte) then break end
     end
 
+    -- if mode 1 and there's been no mavlink traffic for 5000 ms, enable high latency
+    if hl_mode == 1 then
+        if last_seen == gcs:last_seen() then
+            link_lost_for = link_lost_for + 100
+        else
+            -- There has been a new heartbeat, update last_seen and reset link_lost_for
+            last_seen = gcs:last_seen()
+            link_lost_for = 0
+        end
+        if link_lost_for > 5000 and not gcs:get_high_latency_status() then
+            gcs:enable_high_latency_connections(true)
+        elseif link_lost_for < 5000 and gcs:get_high_latency_status() then
+            gcs:enable_high_latency_connections(false)
+        end
+    end
+
     -- send HL2 packet every 5 sec
     if gcs:get_high_latency_status() and (millis():tofloat() * 0.001) -
         time_last_tx > 5 then