diff --git a/libraries/GCS_MAVLink/GCS_MAVLink.cpp b/libraries/GCS_MAVLink/GCS_MAVLink.cpp
index 4bfb6b5f0a..40d8c9daa7 100644
--- a/libraries/GCS_MAVLink/GCS_MAVLink.cpp
+++ b/libraries/GCS_MAVLink/GCS_MAVLink.cpp
@@ -64,6 +64,89 @@ uint8_t mav_var_type(enum ap_var_type t)
 }
 
 
+/// Read a byte from the nominated MAVLink channel
+///
+/// @param chan		Channel to receive on
+/// @returns		Byte read
+///
+uint8_t comm_receive_ch(mavlink_channel_t chan)
+{
+    uint8_t data = 0;
+
+    switch(chan) {
+	case MAVLINK_COMM_0:
+		data = mavlink_comm_0_port->read();
+		break;
+	case MAVLINK_COMM_1:
+		data = mavlink_comm_1_port->read();
+		break;
+#if MAVLINK_COMM_NUM_BUFFERS > 2
+	case MAVLINK_COMM_2:
+		data = mavlink_comm_2_port->read();
+		break;
+#endif
+	default:
+		break;
+	}
+    return data;
+}
+
+/// Check for available transmit space on the nominated MAVLink channel
+///
+/// @param chan		Channel to check
+/// @returns		Number of bytes available
+uint16_t comm_get_txspace(mavlink_channel_t chan)
+{
+	int16_t ret = 0;
+    switch(chan) {
+	case MAVLINK_COMM_0:
+		ret = mavlink_comm_0_port->txspace();
+		break;
+	case MAVLINK_COMM_1:
+		ret = mavlink_comm_1_port->txspace();
+		break;
+#if MAVLINK_COMM_NUM_BUFFERS > 2
+	case MAVLINK_COMM_2:
+		ret = mavlink_comm_2_port->txspace();
+		break;
+#endif
+	default:
+		break;
+	}
+	if (ret < 0) {
+		ret = 0;
+	}
+    return (uint16_t)ret;
+}
+
+/// Check for available data on the nominated MAVLink channel
+///
+/// @param chan		Channel to check
+/// @returns		Number of bytes available
+uint16_t comm_get_available(mavlink_channel_t chan)
+{
+    int16_t bytes = 0;
+    switch(chan) {
+	case MAVLINK_COMM_0:
+		bytes = mavlink_comm_0_port->available();
+		break;
+	case MAVLINK_COMM_1:
+		bytes = mavlink_comm_1_port->available();
+		break;
+#if MAVLINK_COMM_NUM_BUFFERS > 2
+	case MAVLINK_COMM_2:
+		bytes = mavlink_comm_2_port->available();
+		break;
+#endif
+	default:
+		break;
+	}
+	if (bytes == -1) {
+		return 0;
+	}
+    return (uint16_t)bytes;
+}
+
 /*
   send a buffer out a MAVLink channel
  */
diff --git a/libraries/GCS_MAVLink/GCS_MAVLink.h b/libraries/GCS_MAVLink/GCS_MAVLink.h
index 616f5ef3db..a6f8ddd964 100644
--- a/libraries/GCS_MAVLink/GCS_MAVLink.h
+++ b/libraries/GCS_MAVLink/GCS_MAVLink.h
@@ -88,84 +88,20 @@ void comm_send_buffer(mavlink_channel_t chan, const uint8_t *buf, uint8_t len);
 /// @param chan		Channel to receive on
 /// @returns		Byte read
 ///
-static inline uint8_t comm_receive_ch(mavlink_channel_t chan)
-{
-    uint8_t data = 0;
-
-    switch(chan) {
-	case MAVLINK_COMM_0:
-		data = mavlink_comm_0_port->read();
-		break;
-	case MAVLINK_COMM_1:
-		data = mavlink_comm_1_port->read();
-		break;
-#if MAVLINK_COMM_NUM_BUFFERS > 2
-	case MAVLINK_COMM_2:
-		data = mavlink_comm_2_port->read();
-		break;
-#endif
-	default:
-		break;
-	}
-    return data;
-}
+uint8_t comm_receive_ch(mavlink_channel_t chan);
 
 /// Check for available data on the nominated MAVLink channel
 ///
 /// @param chan		Channel to check
 /// @returns		Number of bytes available
-static inline uint16_t comm_get_available(mavlink_channel_t chan)
-{
-    int16_t bytes = 0;
-    switch(chan) {
-	case MAVLINK_COMM_0:
-		bytes = mavlink_comm_0_port->available();
-		break;
-	case MAVLINK_COMM_1:
-		bytes = mavlink_comm_1_port->available();
-		break;
-#if MAVLINK_COMM_NUM_BUFFERS > 2
-	case MAVLINK_COMM_2:
-		bytes = mavlink_comm_2_port->available();
-		break;
-#endif
-	default:
-		break;
-	}
-	if (bytes == -1) {
-		return 0;
-	}
-    return (uint16_t)bytes;
-}
+uint16_t comm_get_available(mavlink_channel_t chan);
 
 
 /// Check for available transmit space on the nominated MAVLink channel
 ///
 /// @param chan		Channel to check
 /// @returns		Number of bytes available
-static inline uint16_t comm_get_txspace(mavlink_channel_t chan)
-{
-	int16_t ret = 0;
-    switch(chan) {
-	case MAVLINK_COMM_0:
-		ret = mavlink_comm_0_port->txspace();
-		break;
-	case MAVLINK_COMM_1:
-		ret = mavlink_comm_1_port->txspace();
-		break;
-#if MAVLINK_COMM_NUM_BUFFERS > 2
-	case MAVLINK_COMM_2:
-		ret = mavlink_comm_2_port->txspace();
-		break;
-#endif
-	default:
-		break;
-	}
-	if (ret < 0) {
-		ret = 0;
-	}
-    return (uint16_t)ret;
-}
+uint16_t comm_get_txspace(mavlink_channel_t chan);
 
 #ifdef HAVE_CRC_ACCUMULATE
 // use the AVR C library implementation. This is a bit over twice as