diff --git a/conf/airframes/examples/quadrotor_lisa_mx.xml b/conf/airframes/examples/quadrotor_lisa_mx.xml
index 6d5bd1f6dd..21450762d6 100644
--- a/conf/airframes/examples/quadrotor_lisa_mx.xml
+++ b/conf/airframes/examples/quadrotor_lisa_mx.xml
@@ -21,7 +21,6 @@
 
     <subsystem name="radio_control" type="spektrum">
       <define name="RADIO_MODE" value="RADIO_AUX1"/>
-      <configure name="USE_SECONDARY_SPEKTRUM_RECEIVER" value="1"/>
     </subsystem>
 
     <subsystem name="motor_mixing"/>
@@ -32,6 +31,10 @@
     <subsystem name="telemetry"     type="transparent"/>
     <subsystem name="imu"           type="lisa_mx_v2.1"/>
     <subsystem name="gps"           type="ublox"/>
+    <subsystem name="gps" type="piksi">
+      <configure name="PIKSI_GPS_PORT" value="UART5"/>
+      <configure name="SECONDARY_GPS" value="piksi"/>
+    </subsystem>
     <subsystem name="stabilization" type="int_quat"/>
     <subsystem name="stabilization" type="rate"/>
     <subsystem name="ahrs"          type="float_mlkf">
diff --git a/conf/firmwares/subsystems/shared/gps_piksi.makefile b/conf/firmwares/subsystems/shared/gps_piksi.makefile
index e6698f1d8f..2ec494afb2 100644
--- a/conf/firmwares/subsystems/shared/gps_piksi.makefile
+++ b/conf/firmwares/subsystems/shared/gps_piksi.makefile
@@ -10,7 +10,7 @@ PIKSI_GPS_PORT_LOWER=$(shell echo $(PIKSI_GPS_PORT) | tr A-Z a-z)
 
 ap.CFLAGS += -DUSE_GPS
 ap.CFLAGS += -DUSE_$(PIKSI_GPS_PORT) -D$(PIKSI_GPS_PORT)_BAUD=B115200
-ap.CFLAGS += -DPIKSI_GPS_LINK=$PIKSI_(GPS_PORT_LOWER)
+ap.CFLAGS += -DPIKSI_GPS_LINK=$(PIKSI_GPS_PORT_LOWER)
 
 ifneq ($(GPS_LED),none)
   ap.CFLAGS += -DGPS_LED=$(GPS_LED)