diff --git a/libraries/SITL/SIM_GPS.cpp b/libraries/SITL/SIM_GPS.cpp
index c65a87729a..4a2479e153 100644
--- a/libraries/SITL/SIM_GPS.cpp
+++ b/libraries/SITL/SIM_GPS.cpp
@@ -996,6 +996,7 @@ uint32_t GPS::CalculateBlockCRC32(uint32_t length, uint8_t *buffer, uint32_t crc
 /*
   temporary method to use file as GPS data
  */
+#if AP_SIM_GPS_FILE_ENABLED
 void GPS::update_file()
 {
     static int fd = -1;
@@ -1027,6 +1028,7 @@ void GPS::update_file()
         lseek(temp_fd, 0, SEEK_SET);
     }
 }
+#endif  // AP_SIM_GPS_FILE_ENABLED
 
 /*
   possibly send a new GPS packet
@@ -1175,9 +1177,11 @@ void GPS::update()
             update_nova(&d);
             break;
 
+#if AP_SIM_GPS_FILE_ENABLED
         case Type::FILE:
             update_file();
             break;
+#endif
     }
 }
 
diff --git a/libraries/SITL/SIM_GPS.h b/libraries/SITL/SIM_GPS.h
index 30e599feba..1244f57338 100644
--- a/libraries/SITL/SIM_GPS.h
+++ b/libraries/SITL/SIM_GPS.h
@@ -35,6 +35,11 @@ param set SERIAL5_PROTOCOL 5
 #define HAL_SIM_GPS_EXTERNAL_FIFO_ENABLED (CONFIG_HAL_BOARD == HAL_BOARD_SITL)
 #endif
 
+#ifndef AP_SIM_GPS_FILE_ENABLED
+// really need to use AP_FileSystem for this.
+#define AP_SIM_GPS_FILE_ENABLED (CONFIG_HAL_BOARD == HAL_BOARD_SITL || CONFIG_HAL_BOARD == HAL_BOARD_LINUX)
+#endif
+
 #include "SIM_SerialDevice.h"
 
 namespace SITL {
@@ -49,7 +54,9 @@ public:
         UBLOX =  1,
         NMEA  =  5,
         SBP   =  6,
+#if AP_SIM_GPS_FILE_ENABLED
         FILE  =  7,
+#endif
         NOVA  =  8,
         SBP2  =  9,
     };
@@ -107,7 +114,9 @@ private:
     void update_sbp(const struct gps_data *d);
     void update_sbp2(const struct gps_data *d);
 
+#if AP_SIM_GPS_FILE_ENABLED
     void update_file();
+#endif
 
     void update_nova(const struct gps_data *d);
     void nova_send_message(uint8_t *header, uint8_t headerlength, uint8_t *payload, uint8_t payloadlen);