diff --git a/conf/airframes/AirborneCodeReorg/LisaFw.xml b/conf/airframes/AirborneCodeReorg/LisaFw.xml
index bfcc14ec98..15baa30976 100644
--- a/conf/airframes/AirborneCodeReorg/LisaFw.xml
+++ b/conf/airframes/AirborneCodeReorg/LisaFw.xml
@@ -185,7 +185,7 @@
 
     <!-- Communication -->
     <subsystem name="telemetry" 	type="transparent">
-      <configure name="MODEM_UART_NR" 	value="2"/>
+      <configure name="MODEM_PORT" 	value="UART2"/>
       <configure name="MODEM_BAUD" 		value="B57600"/>
     </subsystem>
 
@@ -201,7 +201,7 @@
     </subsystem>-->
 
     <subsystem name="gps" 		type="ublox_lea4p">
-      <configure name="GPS_UART_NR"		value="1"/>
+      <configure name="GPS_PORT"		value="UART1"/>
     </subsystem>
 
   </firmware>
diff --git a/conf/airframes/mm/fixed-wing/funjetlisa.xml b/conf/airframes/mm/fixed-wing/funjetlisa.xml
index d6e6556d1c..a92f5d8271 100644
--- a/conf/airframes/mm/fixed-wing/funjetlisa.xml
+++ b/conf/airframes/mm/fixed-wing/funjetlisa.xml
@@ -18,7 +18,7 @@
     <subsystem name="control"/>
     <subsystem name="attitude" 		type="infrared"/>
     <subsystem name="gps" 		type="ublox_lea5h">
-      <param name="GPS_UART_NR"         value="3"/>
+      <configure name="GPS_PORT"         value="UART3"/>
     </subsystem>
     <subsystem name="navigation"/>
   </firmware>
diff --git a/conf/airframes/mm/fixed-wing/funjetlisam.xml b/conf/airframes/mm/fixed-wing/funjetlisam.xml
index 8173da67b3..33e68d8522 100644
--- a/conf/airframes/mm/fixed-wing/funjetlisam.xml
+++ b/conf/airframes/mm/fixed-wing/funjetlisam.xml
@@ -18,7 +18,7 @@
     <subsystem name="control"/>
     <subsystem name="attitude" 		type="infrared"/>
     <subsystem name="gps" 		type="ublox_lea5h">
-      <param name="GPS_UART_NR"         value="3"/>
+      <configure name="GPS_PORT"         value="UART3"/>
     </subsystem>
     <subsystem name="navigation"/>
   </firmware>
diff --git a/conf/airframes/mm/rotor/qmk1.xml b/conf/airframes/mm/rotor/qmk1.xml
index 8935328ed0..81c4f76a00 100644
--- a/conf/airframes/mm/rotor/qmk1.xml
+++ b/conf/airframes/mm/rotor/qmk1.xml
@@ -189,7 +189,6 @@
 
   <firmware name="rotorcraft">
     <target name="ap" board="lisa_l_1.0">
-      <define name="GPS_UART_NR"     value="3"/>
 <!--      <define name="BOOZ_START_DELAY" value="1"/> -->
       <subsystem name="radio_control" type="ppm"/>
       <subsystem name="actuators"     type="mkk"/>
@@ -201,7 +200,9 @@
     </target>
 
     <subsystem name="imu"           type="b2_v1.1"/>
-    <subsystem name="gps"           type="ublox"/>
+    <subsystem name="gps"           type="ublox">
+      <configure name="GPS_PORT"     value="UART3"/>
+    </subsystem>
     <subsystem name="ahrs"          type="cmpl"/>
   </firmware>
 
diff --git a/conf/autopilot/subsystems/fixedwing/gps_ublox_lea4p.makefile b/conf/autopilot/subsystems/fixedwing/gps_ublox_lea4p.makefile
index d4fab5b815..2e3249f679 100644
--- a/conf/autopilot/subsystems/fixedwing/gps_ublox_lea4p.makefile
+++ b/conf/autopilot/subsystems/fixedwing/gps_ublox_lea4p.makefile
@@ -2,9 +2,9 @@
 
 
 ap.CFLAGS += -DUSE_GPS -DUBX
-ap.CFLAGS += -DGPS_LINK=Uart$(GPS_UART_NR)
-ap.CFLAGS += -DUSE_UART$(GPS_UART_NR)
-ap.CFLAGS += -DUART$(GPS_UART_NR)_BAUD=$(GPS_BAUD)
+ap.CFLAGS += -DGPS_LINK=$(GPS_PORT)
+ap.CFLAGS += -DUSE_$(GPS_PORT)
+ap.CFLAGS += -D$(GPS_PORT)_BAUD=$(GPS_BAUD)
 
 ifneq ($(GPS_LED),none)
   ap.CFLAGS += -DGPS_LED=$(GPS_LED)
diff --git a/conf/autopilot/subsystems/fixedwing/gps_ublox_lea5h.makefile b/conf/autopilot/subsystems/fixedwing/gps_ublox_lea5h.makefile
index 27f46bc630..de753df714 100644
--- a/conf/autopilot/subsystems/fixedwing/gps_ublox_lea5h.makefile
+++ b/conf/autopilot/subsystems/fixedwing/gps_ublox_lea5h.makefile
@@ -2,9 +2,9 @@
 
 
 ap.CFLAGS += -DUSE_GPS -DUBX -DGPS_USE_LATLONG
-ap.CFLAGS += -DGPS_LINK=Uart$(GPS_UART_NR)
-ap.CFLAGS += -DUSE_UART$(GPS_UART_NR)
-ap.CFLAGS += -DUART$(GPS_UART_NR)_BAUD=$(GPS_BAUD)
+ap.CFLAGS += -DGPS_LINK=$(GPS_PORT)
+ap.CFLAGS += -DUSE_$(GPS_PORT)
+ap.CFLAGS += -D$(GPS_PORT)_BAUD=$(GPS_BAUD)
 
 ifneq ($(GPS_LED),none)
   ap.CFLAGS += -DGPS_LED=$(GPS_LED)
diff --git a/conf/autopilot/subsystems/fixedwing/telemetry_transparent.makefile b/conf/autopilot/subsystems/fixedwing/telemetry_transparent.makefile
index 8cbcfa9189..c08b83ec9e 100644
--- a/conf/autopilot/subsystems/fixedwing/telemetry_transparent.makefile
+++ b/conf/autopilot/subsystems/fixedwing/telemetry_transparent.makefile
@@ -1,12 +1,8 @@
 
 
-ap.CFLAGS += -DUSE_UART$(MODEM_UART_NR)
-ap.CFLAGS += -DUART$(MODEM_UART_NR)_BAUD=$(MODEM_BAUD)
+ap.CFLAGS += -DUSE_$(MODEM_PORT)
+ap.CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD)
 
-MODEM_UART = Uart$(MODEM_UART_NR)
-
-ap.CFLAGS += -DDOWNLINK -DDOWNLINK_FBW_DEVICE=$(MODEM_UART) -DDOWNLINK_AP_DEVICE=$(MODEM_UART) -DPPRZ_UART=$(MODEM_UART)
+ap.CFLAGS += -DDOWNLINK -DDOWNLINK_FBW_DEVICE=$(MODEM_PORT) -DDOWNLINK_AP_DEVICE=$(MODEM_PORT) -DPPRZ_UART=$(MODEM_PORT)
 ap.CFLAGS += -DDOWNLINK_TRANSPORT=PprzTransport -DDATALINK=PPRZ
 ap.srcs += $(SRC_FIXEDWING)/downlink.c $(SRC_FIRMWARE)/datalink.c $(SRC_FIXEDWING)/pprz_transport.c
-
-
diff --git a/conf/autopilot/subsystems/fixedwing/telemetry_xbee_api.makefile b/conf/autopilot/subsystems/fixedwing/telemetry_xbee_api.makefile
index 3fdff1608d..5dc414e00d 100644
--- a/conf/autopilot/subsystems/fixedwing/telemetry_xbee_api.makefile
+++ b/conf/autopilot/subsystems/fixedwing/telemetry_xbee_api.makefile
@@ -1,10 +1,8 @@
 # XBee modems in API mode
 
-ap.CFLAGS += -DUSE_UART$(MODEM_UART_NR)
-ap.CFLAGS += -DUART$(MODEM_UART_NR)_BAUD=$(MODEM_BAUD)
+ap.CFLAGS += -DUSE_$(MODEM_PORT)
+ap.CFLAGS += -D$(MODEM_PORT)_BAUD=$(MODEM_BAUD)
 
-MODEM_UART = Uart$(MODEM_UART_NR)
-
-ap.CFLAGS += -DDOWNLINK -DDOWNLINK_FBW_DEVICE=$(MODEM_UART) -DDOWNLINK_AP_DEVICE=$(MODEM_UART) -DXBEE_UART=$(MODEM_UART)
+ap.CFLAGS += -DDOWNLINK -DDOWNLINK_FBW_DEVICE=$(MODEM_PORT) -DDOWNLINK_AP_DEVICE=$(MODEM_PORT) -DXBEE_UART=$(MODEM_PORT)
 ap.CFLAGS += -DDOWNLINK_TRANSPORT=XBeeTransport -DDATALINK=XBEE
 ap.srcs += $(SRC_FIXEDWING)/downlink.c $(SRC_FIRMWARE)/datalink.c $(SRC_FIXEDWING)/xbee.c
diff --git a/conf/boards/classix.makefile b/conf/boards/classix.makefile
index 90ae9df340..79002ad107 100644
--- a/conf/boards/classix.makefile
+++ b/conf/boards/classix.makefile
@@ -22,7 +22,7 @@ LPC21ISP_XTAL = 12000
 
 
 ### default settings for classix
-GPS_BAUD	= B38400
+GPS_BAUD = B38400
 GPS_LED = none
 
 # All targets on the TINY board run on the same processor achitecture
diff --git a/conf/boards/hb_1.1.makefile b/conf/boards/hb_1.1.makefile
index 3d20207ebd..88a5accd29 100644
--- a/conf/boards/hb_1.1.makefile
+++ b/conf/boards/hb_1.1.makefile
@@ -30,22 +30,12 @@ MODEM_BAUD = B57600
 endif
 
 ifndef GPS_PORT
-GPS_PORT=UART1
+GPS_PORT = UART1
 endif
 ifndef GPS_BAUD
-GPS_BAUD=B38400
+GPS_BAUD = B38400
 endif
 
-#
-# definitions below were added to get fixedwing firmware to build
-#
-# modem is usualy connected there
-ifndef MODEM_UART_NR
-MODEM_UART_NR = 0
-endif
-ifndef GPS_UART_NR
-GPS_UART_NR	= 1
-endif
 
 ifndef ADC_IR1
 ADC_IR1      = 1
diff --git a/conf/boards/lisa_l_1.0.makefile b/conf/boards/lisa_l_1.0.makefile
index 35717910a1..a78c22e03d 100644
--- a/conf/boards/lisa_l_1.0.makefile
+++ b/conf/boards/lisa_l_1.0.makefile
@@ -69,14 +69,6 @@ MAX_1168_DRDY_PORT_SOURCE = PortSourceGPIOD
 #MAX_1168_DRDY_PORT = GPIOB
 
 
-#
-# definitions below were added to get fixedwing firmware to build
-#
-# modem is usualy connected there
-ifndef MODEM_UART_NR
-MODEM_UART_NR = 2
-endif
-
 ifndef ADC_IR1
 ADC_IR1      = 1
 ADC_IR1_CHAN = 0
diff --git a/conf/boards/lisa_m_1.0.makefile b/conf/boards/lisa_m_1.0.makefile
index 89a1814674..78de8610ed 100644
--- a/conf/boards/lisa_m_1.0.makefile
+++ b/conf/boards/lisa_m_1.0.makefile
@@ -42,8 +42,12 @@ endif
 
 #AHRS_ALIGNER_LED = 7
 
+ifndef GPS_PORT
 GPS_PORT=UART1
+endif
+ifndef GPS_BAUD
 GPS_BAUD=B38400
+endif
 GPS_LED = none
 
 #
@@ -57,13 +61,6 @@ MAX_1168_DRDY_PORT_SOURCE = PortSourceGPIOD
 #MAX_1168_DRDY_PORT = GPIOB
 
 
-#
-# definitions below were added to get fixedwing firmware to build
-#
-# modem is usualy connected there
-ifndef MODEM_UART_NR
-MODEM_UART_NR = 2
-endif
 
 ifndef ADC_IR1
 ADC_IR1      = 1
@@ -80,6 +77,3 @@ endif
 ifndef ADC_IR_NB_SAMPLES
 ADC_IR_NB_SAMPLES = 16
 endif
-ifndef GPS_UART_NR
-GPS_UART_NR	= 1
-endif
diff --git a/conf/boards/tiny_0.99.makefile b/conf/boards/tiny_0.99.makefile
index 22e454ffcd..1b077c6b40 100644
--- a/conf/boards/tiny_0.99.makefile
+++ b/conf/boards/tiny_0.99.makefile
@@ -13,6 +13,6 @@ BOARD_VERSION=0.99
 
 BOARD_CFG=\"boards/$(BOARD)_$(BOARD_VERSION).h\"
 
-GPS_UART_NR	= 1
+GPS_PORT = UART1
 GPS_LED = none
-MODEM_UART_NR = 0
+MODEM_PORT = UART0
diff --git a/conf/boards/tiny_1.1.makefile b/conf/boards/tiny_1.1.makefile
index 538b7b186f..7250804216 100644
--- a/conf/boards/tiny_1.1.makefile
+++ b/conf/boards/tiny_1.1.makefile
@@ -13,6 +13,6 @@ BOARD_VERSION=1.1
 
 BOARD_CFG=\"boards/$(BOARD)_$(BOARD_VERSION).h\"
 
-GPS_UART_NR	= 1
+GPS_PORT = UART1
 GPS_LED = none
-MODEM_UART_NR = 0
+MODEM_PORT = UART0
diff --git a/conf/boards/tiny_2.11.makefile b/conf/boards/tiny_2.11.makefile
index 9faf7301a9..392eb13482 100644
--- a/conf/boards/tiny_2.11.makefile
+++ b/conf/boards/tiny_2.11.makefile
@@ -21,11 +21,20 @@ LPC21ISP_XTAL = 12000
 
 
 ### default settings for tiny_2 and twog
-GPS_UART_NR	= 0
+ifndef GPS_PORT
+GPS_PORT	= UART0
+endif
+ifndef GPS_BAUD
 GPS_BAUD	= B38400
+endif
 GPS_LED     = 2
-MODEM_UART_NR	= 1
+
+ifndef MODEM_PORT
+MODEM_PORT	= UART1
+endif
+ifndef MODEM_BAUD
 MODEM_BAUD 	= B57600
+endif
 
 ADC_IR_TOP = ADC_0
 ADC_IR1 = ADC_1
diff --git a/sw/airborne/Makefile b/sw/airborne/Makefile
index adb2189087..f969cc7499 100644
--- a/sw/airborne/Makefile
+++ b/sw/airborne/Makefile
@@ -42,6 +42,14 @@ ifneq ($(MAKECMDGOALS),clean)
   endif
 endif
 
+# check for obsolete MODEM_UART_NR and GPS_UART_NR makefile vars
+ifdef GPS_UART_NR
+  $(error GPS_UART_NR is obsolete, please use GPS_PORT instead to define the Uart to use, e.g. <configure name="GPS_PORT" value="UART1"/>)
+endif
+ifdef MODEM_UART_NR
+  $(error MODEM_UART_NR is obsolete, please use MODEM_PORT instead to define the Uart to use, e.g. <configure name="MODEM_PORT" value="UART1"/>)
+endif
+
 $(TARGET).install : warn_conf
 
 warn_conf :