diff --git a/conf/modules/airspeed_amsys.xml b/conf/modules/airspeed_amsys.xml
index 5deffea0fb..000b2a424b 100644
--- a/conf/modules/airspeed_amsys.xml
+++ b/conf/modules/airspeed_amsys.xml
@@ -34,11 +34,7 @@
   <event fun="AirspeedAmsysEvent()"/>
 
   <makefile>
-    <raw>
-      AIRSPEED_AMSYS_I2C_DEV ?= i2c0
-      AIRSPEED_AMSYS_I2C_DEV_LOWER=$(shell echo $(AIRSPEED_AMSYS_I2C_DEV) | tr A-Z a-z)
-      AIRSPEED_AMSYS_I2C_DEV_UPPER=$(shell echo $(AIRSPEED_AMSYS_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="AIRSPEED_AMSYS_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(AIRSPEED_AMSYS_I2C_DEV_UPPER)"/>
     <define name="AIRSPEED_AMSYS_I2C_DEV" value="$(AIRSPEED_AMSYS_I2C_DEV_LOWER)"/>
     <file name="airspeed_amsys.c"/>
diff --git a/conf/modules/airspeed_ets.xml b/conf/modules/airspeed_ets.xml
index 51cb506ba4..55ad1bf922 100644
--- a/conf/modules/airspeed_ets.xml
+++ b/conf/modules/airspeed_ets.xml
@@ -36,11 +36,7 @@
   <event fun="AirspeedEtsEvent()"/>
 
   <makefile>
-    <raw>
-      AIRSPEED_ETS_I2C_DEV ?= i2c0
-      AIRSPEED_ETS_I2C_DEV_LOWER=$(shell echo $(AIRSPEED_ETS_I2C_DEV) | tr A-Z a-z)
-      AIRSPEED_ETS_I2C_DEV_UPPER=$(shell echo $(AIRSPEED_ETS_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="AIRSPEED_ETS_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(AIRSPEED_ETS_I2C_DEV_UPPER)"/>
     <define name="AIRSPEED_ETS_I2C_DEV" value="$(AIRSPEED_ETS_I2C_DEV_LOWER)"/>
     <file name="airspeed_ets.c"/>
diff --git a/conf/modules/airspeed_otf.xml b/conf/modules/airspeed_otf.xml
index 28229c085d..fb4a1fa541 100644
--- a/conf/modules/airspeed_otf.xml
+++ b/conf/modules/airspeed_otf.xml
@@ -22,13 +22,11 @@
   <periodic fun="airspeed_otf_periodic()" freq="1"/>
   <event fun="airspeed_otf_event()"/>
   <makefile target="ap">
-    <raw>
-      OTF_UART_LOWER=$(shell echo $(OTF_UART) | tr A-Z a-z)
-    </raw>
+    <configure name="OTF_UART" case="upper|lower"/>
     <file name="airspeed_otf.c"/>
-    <define name="USE_$(OTF_UART)"/>
+    <define name="USE_$(OTF_UART_UPPER)"/>
     <define name="MET_LINK" value="$(OTF_UART_LOWER)"/>
-    <define name="$(OTF_UART)_BAUD" value="B115200"/>
+    <define name="$(OTF_UART_UPPER)_BAUD" value="B115200"/>
   </makefile>
 </module>
 
diff --git a/conf/modules/baro_amsys.xml b/conf/modules/baro_amsys.xml
index 5517515208..f4414a228f 100644
--- a/conf/modules/baro_amsys.xml
+++ b/conf/modules/baro_amsys.xml
@@ -30,11 +30,7 @@
   <event fun="BaroAmsysEvent()"/>
 
   <makefile target="ap">
-    <raw>
-      BARO_AMSYS_I2C_DEV ?= i2c0
-      BARO_AMSYS_I2C_DEV_LOWER=$(shell echo $(BARO_AMSYS_I2C_DEV) | tr A-Z a-z)
-      BARO_AMSYS_I2C_DEV_UPPER=$(shell echo $(BARO_AMSYS_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="BARO_AMSYS_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(BARO_AMSYS_I2C_DEV_UPPER)"/>
     <define name="BARO_AMSYS_I2C_DEV" value="$(BARO_AMSYS_I2C_DEV_LOWER)"/>
     <file name="baro_amsys.c"/>
diff --git a/conf/modules/baro_bmp.xml b/conf/modules/baro_bmp.xml
index 0b1cdf9530..457598c436 100644
--- a/conf/modules/baro_bmp.xml
+++ b/conf/modules/baro_bmp.xml
@@ -13,11 +13,7 @@
   <periodic fun="baro_bmp_periodic()" freq="15"/>
   <event fun="baro_bmp_event()"/>
   <makefile target="ap">
-    <raw>
-      BMP_I2C_DEV ?= i2c0
-      BMP_I2C_DEV_LOWER=$(shell echo $(BMP_I2C_DEV) | tr A-Z a-z)
-      BMP_I2C_DEV_UPPER=$(shell echo $(BMP_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="BMP_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(BMP_I2C_DEV_UPPER)"/>
     <define name="BMP_I2C_DEV" value="$(BMP_I2C_DEV_LOWER)"/>
     <file name="baro_bmp.c"/>
diff --git a/conf/modules/baro_ets.xml b/conf/modules/baro_ets.xml
index 9bab9384b4..1e155c60a0 100644
--- a/conf/modules/baro_ets.xml
+++ b/conf/modules/baro_ets.xml
@@ -34,11 +34,7 @@
   <event fun="BaroEtsEvent()"/>
 
   <makefile target="ap">
-    <raw>
-      BARO_ETS_I2C_DEV ?= i2c0
-      BARO_ETS_I2C_DEV_LOWER=$(shell echo $(BARO_ETS_I2C_DEV) | tr A-Z a-z)
-      BARO_ETS_I2C_DEV_UPPER=$(shell echo $(BARO_ETS_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="BARO_ETS_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(BARO_ETS_I2C_DEV_UPPER)"/>
     <define name="BARO_ETS_I2C_DEV" value="$(BARO_ETS_I2C_DEV_LOWER)"/>
     <file name="baro_ets.c"/>
diff --git a/conf/modules/baro_hca.xml b/conf/modules/baro_hca.xml
index b4c25f0b98..a6fe0bbfa0 100644
--- a/conf/modules/baro_hca.xml
+++ b/conf/modules/baro_hca.xml
@@ -14,11 +14,7 @@
   <event fun="BaroHcaEvent()"/>
 
   <makefile target="ap">
-    <raw>
-      BARO_HCA_I2C_DEV ?= i2c0
-      BARO_HCA_I2C_DEV_LOWER=$(shell echo $(BARO_HCA_I2C_DEV) | tr A-Z a-z)
-      BARO_HCA_I2C_DEV_UPPER=$(shell echo $(BARO_HCA_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="BARO_HCA_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(BARO_HCA_I2C_DEV_UPPER)"/>
     <define name="BARO_HCA_I2C_DEV" value="$(BARO_HCA_I2C_DEV_LOWER)"/>
     <file name="baro_hca.c"/>
diff --git a/conf/modules/baro_ms5611_i2c.xml b/conf/modules/baro_ms5611_i2c.xml
index 49268e25ec..189eb8192d 100644
--- a/conf/modules/baro_ms5611_i2c.xml
+++ b/conf/modules/baro_ms5611_i2c.xml
@@ -17,11 +17,7 @@
   <periodic fun="baro_ms5611_periodic_check()" freq="40"/>
   <event fun="baro_ms5611_event()"/>
   <makefile target="ap">
-    <raw>
-      MS5611_I2C_DEV ?= i2c0
-      MS5611_I2C_DEV_LOWER=$(shell echo $(MS5611_I2C_DEV) | tr A-Z a-z)
-      MS5611_I2C_DEV_UPPER=$(shell echo $(MS5611_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="MS5611_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(MS5611_I2C_DEV_UPPER)"/>
     <define name="MS5611_I2C_DEV" value="$(MS5611_I2C_DEV_LOWER)"/>
     <file name="baro_ms5611_i2c.c"/>
diff --git a/conf/modules/baro_ms5611_spi.xml b/conf/modules/baro_ms5611_spi.xml
index 0ab146a0ad..2739d55496 100644
--- a/conf/modules/baro_ms5611_spi.xml
+++ b/conf/modules/baro_ms5611_spi.xml
@@ -18,15 +18,9 @@
   <periodic fun="baro_ms5611_periodic_check()" freq="40"/>
   <event fun="baro_ms5611_event()"/>
   <makefile target="ap">
+    <configure name="MS5611_SPI_DEV" value="spi1" default="TRUE" case="upper|lower"/>
+    <configure name="MS5611_SLAVE_IDX" value="spi_slave0" default="TRUE" case="upper|lower"/>
     <raw>
-      MS5611_SPI_DEV ?= spi1
-      MS5611_SPI_DEV_LOWER=$(shell echo $(MS5611_SPI_DEV) | tr A-Z a-z)
-      MS5611_SPI_DEV_UPPER=$(shell echo $(MS5611_SPI_DEV) | tr a-z A-Z)
-
-      MS5611_SLAVE_IDX ?= spi_slave0
-      MS5611_SLAVE_IDX_LOWER=$(shell echo $(MS5611_SLAVE_IDX) | tr A-Z a-z)
-      MS5611_SLAVE_IDX_UPPER=$(shell echo $(MS5611_SLAVE_IDX) | tr a-z A-Z)
-
       include $(CFG_SHARED)/spi_master.makefile
     </raw>
     <define name="USE_$(MS5611_SPI_DEV_UPPER)" />
diff --git a/conf/modules/baro_scp_i2c.xml b/conf/modules/baro_scp_i2c.xml
index 1b71ee439c..227d5a1066 100644
--- a/conf/modules/baro_scp_i2c.xml
+++ b/conf/modules/baro_scp_i2c.xml
@@ -13,11 +13,7 @@
   <periodic fun="baro_scp_periodic()" freq="1.8"/>
   <event fun="baro_scp_event()"/>
   <makefile target="ap">
-    <raw>
-      SCP_I2C_DEV ?= i2c0
-      SCP_I2C_DEV_LOWER=$(shell echo $(SCP_I2C_DEV) | tr A-Z a-z)
-      SCP_I2C_DEV_UPPER=$(shell echo $(SCP_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="SCP_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(SCP_I2C_DEV_UPPER)"/>
     <define name="SCP_I2C_DEV" value="$(SCP_I2C_DEV_LOWER)"/>
     <file name="baro_scp_i2c.c"/>
diff --git a/conf/modules/digital_cam_i2c.xml b/conf/modules/digital_cam_i2c.xml
index 975f9593cf..906e753b0f 100644
--- a/conf/modules/digital_cam_i2c.xml
+++ b/conf/modules/digital_cam_i2c.xml
@@ -27,11 +27,7 @@
   <datalink message="PAYLOAD_COMMAND" fun="ParseCameraCommand()"/>
 
   <makefile target="ap">
-    <raw>
-      ATMEGA_I2C_DEV ?= i2c0
-      ATMEGA_I2C_DEV_LOWER=$(shell echo $(ATMEGA_I2C_DEV) | tr A-Z a-z)
-      ATMEGA_I2C_DEV_UPPER=$(shell echo $(ATMEGA_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="ATMEGA_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(ATMEGA_I2C_DEV_UPPER)"/>
     <define name="ATMEGA_I2C_DEV" value="$(ATMEGA_I2C_DEV_LOWER)"/>
     <file name="atmega_i2c_cam_ctrl.c"/>
diff --git a/conf/modules/digital_cam_uart.xml b/conf/modules/digital_cam_uart.xml
index 486a2affba..c734d8ec16 100644
--- a/conf/modules/digital_cam_uart.xml
+++ b/conf/modules/digital_cam_uart.xml
@@ -70,12 +70,10 @@
     <file name="uart_cam_ctrl.c"/>
     <file name="catia/protocol.c"/>
     <file name="dc.c"/>
-    <raw>
-CAMERA_PORT_LOWER=$(shell echo $(CAMERA_PORT) | tr A-Z a-z)
-$(TARGET).CFLAGS += -D$(CAMERA_PORT)_BAUD=B115200
-    </raw>
-    <define name="USE_$(CAMERA_PORT)"/>
+    <configure name="CAMERA_PORT" case="upper|lower"/>
+    <define name="USE_$(CAMERA_PORT_UPPER)"/>
     <define name="CAMERA_LINK" value="$(CAMERA_PORT_LOWER)"/>
+    <define name="$(CAMERA_PORT_UPPER)_BAUD" value="B115200"/>
   </makefile>
 </module>
 
diff --git a/conf/modules/direct_memory_logger.xml b/conf/modules/direct_memory_logger.xml
index de2d437321..f4c74b9022 100644
--- a/conf/modules/direct_memory_logger.xml
+++ b/conf/modules/direct_memory_logger.xml
@@ -27,19 +27,10 @@
   <periodic fun="direct_memory_logger_periodic()" autorun="TRUE"/>
 
   <makefile target="ap">
+    <configure name="DM_LOG_UART" value="uart1" default="TRUE" case="upper|lower"/>
+    <configure name="DM_LOG_SPI_DEV" value="spi2" default="TRUE" case="upper|lower"/>
+    <configure name="DM_LOG_SPI_SLAVE_IDX" value="spi_slave1" default="TRUE" case="upper|lower"/>
     <raw>
-      DM_LOG_UART ?= uart1
-      DM_LOG_UART_LOWER=$(shell echo $(DM_LOG_UART) | tr A-Z a-z)
-      DM_LOG_UART_UPPER=$(shell echo $(DM_LOG_UART) | tr a-z A-Z)
-
-      DM_LOG_SPI_DEV ?= spi2
-      DM_LOG_SPI_DEV_LOWER=$(shell echo $(DM_LOG_SPI_DEV) | tr A-Z a-z)
-      DM_LOG_SPI_DEV_UPPER=$(shell echo $(DM_LOG_SPI_DEV) | tr a-z A-Z)
-
-      DM_LOG_SPI_SLAVE_IDX ?= spi_slave1
-      DM_LOG_SPI_SLAVE_IDX_LOWER=$(shell echo $(DM_LOG_SPI_SLAVE_IDX) | tr A-Z a-z)
-      DM_LOG_SPI_SLAVE_IDX_UPPER=$(shell echo $(DM_LOG_SPI_SLAVE_IDX) | tr a-z A-Z)
-
       include $(CFG_SHARED)/spi_master.makefile
     </raw>
 
diff --git a/conf/modules/extra_dl.xml b/conf/modules/extra_dl.xml
index 21ced1bc68..b1d4069f27 100644
--- a/conf/modules/extra_dl.xml
+++ b/conf/modules/extra_dl.xml
@@ -12,12 +12,10 @@
   <init fun="extra_pprz_dl_init()"/>
   <event fun="ExtraDatalinkEvent()"/>
   <makefile target="ap">
-    <raw>
-EXTRA_DL_PORT_LOWER = $(shell echo $(EXTRA_DL_PORT) | tr A-Z a-z)
-    </raw>
+    <configure name="EXTRA_DL_PORT" case="upper|lower"/>
     <define name="EXTRA_DOWNLINK_DEVICE" value="$(EXTRA_DL_PORT_LOWER)"/>
-    <define name="USE_$(EXTRA_DL_PORT)"/>
-    <define name="$(EXTRA_DL_PORT)_BAUD" value="$(EXTRA_DL_BAUD)"/>
+    <define name="USE_$(EXTRA_DL_PORT_UPPER)"/>
+    <define name="$(EXTRA_DL_PORT_UPPER)_BAUD" value="$(EXTRA_DL_BAUD)"/>
     <file name="extra_pprz_dl.c"/>
     <file name="pprz_transport.c" dir="subsystems/datalink"/>
   </makefile>
diff --git a/conf/modules/ezcurrent.xml b/conf/modules/ezcurrent.xml
index a748b79499..5780d49103 100644
--- a/conf/modules/ezcurrent.xml
+++ b/conf/modules/ezcurrent.xml
@@ -14,11 +14,7 @@
   <event fun="ezcurrent_read_event()"/>
 
   <makefile target="ap">
-    <raw>
-      EZCURRENT_I2C_DEV ?= i2c0
-      EZCURRENT_I2C_DEV_LOWER=$(shell echo $(EZCURRENT_I2C_DEV) | tr A-Z a-z)
-      EZCURRENT_I2C_DEV_UPPER=$(shell echo $(EZCURRENT_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="EZCURRENT_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(EZCURRENT_I2C_DEV_UPPER)"/>
     <define name="EZCURRENT_I2C_DEV" value="$(EZCURRENT_I2C_DEV_LOWER)"/>
     <file name="ezcurrent.c"/>
diff --git a/conf/modules/generic_com.xml b/conf/modules/generic_com.xml
index 42470d8453..1eb9386a3f 100644
--- a/conf/modules/generic_com.xml
+++ b/conf/modules/generic_com.xml
@@ -16,11 +16,7 @@
   <periodic fun="generic_com_periodic()" period="180" start="start_com()" stop="stop_com()" autorun="TRUE"/>
   <event fun="generic_com_event()"/>
   <makefile>
-    <raw>
-      GENERIC_COM_I2C_DEV ?= i2c0
-      GENERIC_COM_I2C_DEV_LOWER=$(shell echo $(GENERIC_COM_I2C_DEV) | tr A-Z a-z)
-      GENERIC_COM_I2C_DEV_UPPER=$(shell echo $(GENERIC_COM_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="GENERIC_COM_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(GENERIC_COM_I2C_DEV_UPPER)"/>
     <define name="GENERIC_COM_I2C_DEV" value="$(GENERIC_COM_I2C_DEV_LOWER)"/>
     <file name="generic_com.c"/>
diff --git a/conf/modules/gps_ublox.xml b/conf/modules/gps_ublox.xml
index 1f293e7d8b..a082a92d26 100644
--- a/conf/modules/gps_ublox.xml
+++ b/conf/modules/gps_ublox.xml
@@ -21,15 +21,14 @@
     <file name="gps.c" dir="subsystems"/>
     <file name="gps_ubx.c" dir="subsystems/gps"/>
     <define name="USE_GPS"/>
+    <configure name="GPS_PORT" case="upper|lower"/>
+    <define name="USE_$(GPS_PORT_UPPER)"/>
+    <define name="GPS_LINK" value="$(GPS_PORT_LOWER)"/>
+    <define name="$(GPS_PORT_UPPER)_BAUD" value="$(GPS_BAUD)"/>
+    <configure name="GPS_LED" value="none" default="TRUE"/>
+    <define name="GPS_LED" value="$(GPS_LED)" cond="ifneq ($(GPS_LED),none)"/>
     <raw>
-      UBX_GPS_PORT_LOWER=$(shell echo $(GPS_PORT) | tr A-Z a-z)
       ap.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_ubx.h\"
-      ap.CFLAGS += -DUSE_$(GPS_PORT) -D$(GPS_PORT)_BAUD=$(GPS_BAUD)
-      ap.CFLAGS += -DUSE_GPS -DGPS_LINK=$(UBX_GPS_PORT_LOWER)
-      GPS_LED ?= none
-      ifneq ($(GPS_LED),none)
-        ap.CFLAGS += -DGPS_LED=$(GPS_LED)
-      endif
     </raw>
   </makefile>
   <makefile target="nps">
diff --git a/conf/modules/hott_telemetry.xml b/conf/modules/hott_telemetry.xml
index d7c1ee6ba5..e5c3feef3a 100644
--- a/conf/modules/hott_telemetry.xml
+++ b/conf/modules/hott_telemetry.xml
@@ -25,18 +25,11 @@
 
   <makefile target="ap">
     <file name="hott.c"/>
-
-    <raw>
-      HOTT_PORT ?= UART1
-      HOTT_PORT_LOWER=$(shell echo $(HOTT_PORT) | tr A-Z a-z)
-      HOTT_PORT_UPPER=$(shell echo $(HOTT_PORT) | tr a-z A-Z)
-
-      HOTT_SIM_EAM_SENSOR   ?= 1
-      HOTT_SIM_GAM_SENSOR   ?= 0
-      HOTT_SIM_GPS_SENSOR   ?= 0
-      HOTT_SIM_VARIO_SENSOR ?= 0
-    </raw>
-
+    <configure name="HOTT_PORT" value="uart1" default="TRUE" case="upper|lower"/>
+    <configure name="HOTT_SIM_EAM_SENSOR" value="1" default="TRUE"/>
+    <configure name="HOTT_SIM_GAM_SENSOR" value="0" default="TRUE"/>
+    <configure name="HOTT_SIM_GPS_SENSOR" value="0" default="TRUE"/>
+    <configure name="HOTT_SIM_VARIO_SENSOR" value="0" default="TRUE"/>
     <define name="HOTT_PORT" value="$(HOTT_PORT_LOWER)"/>
     <define name="USE_$(HOTT_PORT_UPPER)"/>
     <define name="$(HOTT_PORT_UPPER)_BAUD" value="B19200"/>
@@ -44,7 +37,6 @@
     <define name="HOTT_SIM_GAM_SENSOR" value="$(HOTT_SIM_GAM_SENSOR)"/>
     <define name="HOTT_SIM_GPS_SENSOR" value="$(HOTT_SIM_GPS_SENSOR)"/>
     <define name="HOTT_SIM_VARIO_SENSOR" value="$(HOTT_SIM_VARIO_SENSOR)"/>
-
   </makefile>
 </module>
 
diff --git a/conf/modules/humid_htm_b71.xml b/conf/modules/humid_htm_b71.xml
index 9500907ed2..7f90242ea2 100644
--- a/conf/modules/humid_htm_b71.xml
+++ b/conf/modules/humid_htm_b71.xml
@@ -13,11 +13,7 @@
   <periodic fun="humid_htm_read()"  freq="4" delay="14"/>
   <event fun="humid_htm_event()"/>
   <makefile target="ap">
-    <raw>
-      HTM_I2C_DEV ?= i2c0
-      HTM_I2C_DEV_LOWER=$(shell echo $(HTM_I2C_DEV) | tr A-Z a-z)
-      HTM_I2C_DEV_UPPER=$(shell echo $(HTM_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="HTM_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(HTM_I2C_DEV_UPPER)"/>
     <define name="HTM_I2C_DEV" value="$(HTM_I2C_DEV_LOWER)"/>
     <file name="humid_htm_b71.c"/>
diff --git a/conf/modules/imu_mpu9250.xml b/conf/modules/imu_mpu9250.xml
index 5ff64c6dfb..4b9579265b 100644
--- a/conf/modules/imu_mpu9250.xml
+++ b/conf/modules/imu_mpu9250.xml
@@ -17,11 +17,7 @@
   <periodic fun="imu_mpu9250_report()" freq="10" autorun="TRUE"/>
   <event fun="imu_mpu9250_event()"/>
   <makefile>
-    <raw>
-      IMU_MPU9250_I2C_DEV ?= i2c1
-      IMU_MPU9250_I2C_DEV_LOWER=$(shell echo $(IMU_MPU9250_I2C_DEV) | tr A-Z a-z)
-      IMU_MPU9250_I2C_DEV_UPPER=$(shell echo $(IMU_MPU9250_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="IMU_MPU9250_I2C_DEV" value="i2c1" default="TRUE" case="upper|lower"/>
     <define name="USE_$(IMU_MPU9250_I2C_DEV_UPPER)"/>
     <define name="IMU_MPU9250_I2C_DEV" value="$(IMU_MPU9250_I2C_DEV_LOWER)"/>
     <file name="imu_mpu9250.c"/>
diff --git a/conf/modules/ins_vn100.xml b/conf/modules/ins_vn100.xml
index 8ac6d14606..f2a77bcd1f 100644
--- a/conf/modules/ins_vn100.xml
+++ b/conf/modules/ins_vn100.xml
@@ -15,15 +15,9 @@
   <periodic fun="vn100_report_task()" freq="4"/>
   <event fun="vn100_event_task()"/>
   <makefile>
+    <configure name="VN100_SPI_DEV" value="spi1" default="TRUE" case="upper|lower"/>
+    <configure name="VN100_SLAVE_IDX" value="spi_slave0" default="TRUE" case="upper|lower"/>
     <raw>
-      VN100_SPI_DEV ?= spi1
-      VN100_SPI_DEV_LOWER=$(shell echo $(VN100_SPI_DEV) | tr A-Z a-z)
-      VN100_SPI_DEV_UPPER=$(shell echo $(VN100_SPI_DEV) | tr a-z A-Z)
-
-      VN100_SLAVE_IDX ?= spi_slave0
-      VN100_SLAVE_IDX_LOWER=$(shell echo $(VN100_SLAVE_IDX) | tr A-Z a-z)
-      VN100_SLAVE_IDX_UPPER=$(shell echo $(VN100_SLAVE_IDX) | tr a-z A-Z)
-
       include $(CFG_SHARED)/spi_master.makefile
     </raw>
     <define name="USE_$(VN100_SPI_DEV_UPPER)" />
diff --git a/conf/modules/logger_dataflash.xml b/conf/modules/logger_dataflash.xml
index 453394d7a2..fa1b606265 100644
--- a/conf/modules/logger_dataflash.xml
+++ b/conf/modules/logger_dataflash.xml
@@ -39,19 +39,9 @@ For more informations on how to use this module you can refer to the wiki : http
   <periodic fun="high_speed_logger_direct_memory_periodic()" autorun="TRUE"/>
   <makefile>
 
-    <raw>
-      HS_LOG_UART ?= uart3
-      HS_LOG_UART_LOWER=$(shell echo $(HS_LOG_UART) | tr A-Z a-z)
-      HS_LOG_UART_UPPER=$(shell echo $(HS_LOG_UART) | tr a-z A-Z)
-
-      HS_LOG_SPI ?= spi1
-      HS_LOG_SPI_LOWER=$(shell echo $(HS_LOG_SPI) | tr A-Z a-z)
-      HS_LOG_SPI_UPPER=$(shell echo $(HS_LOG_SPI) | tr a-z A-Z)
-
-      HS_LOG_SPI_SLAVE ?= spi_slave1
-      HS_LOG_SPI_SLAVE_LOWER=$(shell echo $(HS_LOG_SPI_SLAVE) | tr A-Z a-z)
-      HS_LOG_SPI_SLAVE_UPPER=$(shell echo $(HS_LOG_SPI_SLAVE) | tr a-z A-Z)
-    </raw>
+    <configure name="HS_LOG_UART" value="uart3" default="TRUE" case="upper|lower"/>
+    <configure name="HS_LOG_SPI" value="spi1" default="TRUE" case="upper|lower"/>
+    <configure name="HS_LOG_SPI_SLAVE" value="spi_slave1" default="TRUE" case="upper|lower"/>
 
     <define name="SPI_MASTER" value="1" />
     <define name="USE_$(HS_LOG_SPI_UPPER)" value="1" />
diff --git a/conf/modules/logger_sd_spi_direct.xml b/conf/modules/logger_sd_spi_direct.xml
index 259054105e..1c35c84f49 100644
--- a/conf/modules/logger_sd_spi_direct.xml
+++ b/conf/modules/logger_sd_spi_direct.xml
@@ -38,22 +38,12 @@ Do not use start/stop functionality of the module, the module is not intended to
   <datalink message="SETTING" fun="sdlogger_spi_direct_command()"/>
   <makefile target="ap">
 
+    <configure name="SDLOGGER_DIRECT_SPI" value="spi2" default="TRUE" case="upper|lower"/>
+    <configure name="SDLOGGER_DIRECT_SPI_SLAVE" value="spi_slave2" default="TRUE" case="upper|lower"/>
+    <configure name="SDLOGGER_DIRECT_CONTROL_SWITCH" value="RADIO_AUX2" default="TRUE"/>
+    <configure name="LOGGER_LED" value="none" default="TRUE"/>
+    <define name="LOGGER_LED" value="$(LOGGER_LED)" cond="ifneq ($(LOGGER_LED),none)"/>
     <raw>
-        SDLOGGER_DIRECT_SPI ?= spi2
-        SDLOGGER_DIRECT_SPI_LOWER=$(shell echo $(SDLOGGER_DIRECT_SPI) | tr A-Z a-z)
-        SDLOGGER_DIRECT_SPI_UPPER=$(shell echo $(SDLOGGER_DIRECT_SPI) | tr a-z A-Z)
-
-        SDLOGGER_DIRECT_SPI_SLAVE ?= spi_slave2
-        SDLOGGER_DIRECT_SPI_SLAVE_LOWER=$(shell echo $(SDLOGGER_DIRECT_SPI_SLAVE) | tr A-Z a-z)
-        SDLOGGER_DIRECT_SPI_SLAVE_UPPER=$(shell echo $(SDLOGGER_DIRECT_SPI_SLAVE) | tr a-z A-Z)
-
-        SDLOGGER_DIRECT_CONTROL_SWITCH ?= RADIO_AUX2
-
-        LOGGER_LED ?= none
-        ifneq ($(LOGGER_LED),none)
-        ap.CFLAGS += -DLOGGER_LED=$(LOGGER_LED)
-        endif
-
         include $(CFG_SHARED)/sdlog.makefile
         include $(CFG_SHARED)/spi_master.makefile
     </raw>
diff --git a/conf/modules/logger_spi_link.xml b/conf/modules/logger_spi_link.xml
index 8f97dc0f03..fea247d899 100644
--- a/conf/modules/logger_spi_link.xml
+++ b/conf/modules/logger_spi_link.xml
@@ -12,15 +12,9 @@
   <init fun="high_speed_logger_spi_link_init()"/>
   <periodic fun="high_speed_logger_spi_link_periodic()" autorun="TRUE"/>
   <makefile target="ap">
+    <configure name="HS_LOG_SPI_DEV" value="spi1" default="TRUE" case="upper|lower"/>
+    <configure name="HS_LOG_SPI_SLAVE_IDX" value="spi_slave1" default="TRUE" case="upper|lower"/>
     <raw>
-      HS_LOG_SPI_DEV ?= spi1
-      HS_LOG_SPI_DEV_LOWER=$(shell echo $(HS_LOG_SPI_DEV) | tr A-Z a-z)
-      HS_LOG_SPI_DEV_UPPER=$(shell echo $(HS_LOG_SPI_DEV) | tr a-z A-Z)
-
-      HS_LOG_SPI_SLAVE_IDX ?= spi_slave1
-      HS_LOG_SPI_SLAVE_IDX_LOWER=$(shell echo $(HS_LOG_SPI_SLAVE_IDX) | tr A-Z a-z)
-      HS_LOG_SPI_SLAVE_IDX_UPPER=$(shell echo $(HS_LOG_SPI_SLAVE_IDX) | tr a-z A-Z)
-
       include $(CFG_SHARED)/spi_master.makefile
     </raw>
 
diff --git a/conf/modules/mag_hmc5843.xml b/conf/modules/mag_hmc5843.xml
index c14e5801a2..c18fed99b5 100644
--- a/conf/modules/mag_hmc5843.xml
+++ b/conf/modules/mag_hmc5843.xml
@@ -12,11 +12,7 @@
   <periodic fun="hmc5843_module_periodic()" freq="60"/>
   <event fun="hmc5843_module_event()"/>
   <makefile>
-    <raw>
-      HMC5843_I2C_DEV ?= i2c0
-      HMC5843_I2C_DEV_LOWER=$(shell echo $(HMC5843_I2C_DEV) | tr A-Z a-z)
-      HMC5843_I2C_DEV_UPPER=$(shell echo $(HMC5843_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="HMC5843_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(HMC5843_I2C_DEV_UPPER)"/>
     <define name="HMC5843_I2C_DEV" value="$(HMC5843_I2C_DEV_LOWER)"/>
     <file name="mag_hmc5843.c"/>
diff --git a/conf/modules/mag_hmc58xx.xml b/conf/modules/mag_hmc58xx.xml
index 85dc38feb5..0205a3554d 100644
--- a/conf/modules/mag_hmc58xx.xml
+++ b/conf/modules/mag_hmc58xx.xml
@@ -25,9 +25,8 @@
       ifeq ($(MAG_HMC58XX_I2C_DEV),)
         $(error mag_hmc58xx module error: please configure MAG_HMC58XX_I2C_DEV)
       endif
-      MAG_HMC58XX_I2C_DEV_UPPER=$(shell echo $(MAG_HMC58XX_I2C_DEV) | tr a-z A-Z)
-      MAG_HMC58XX_I2C_DEV_LOWER=$(shell echo $(MAG_HMC58XX_I2C_DEV) | tr A-Z a-z)
     </raw>
+    <configure name="MAG_HMC58XX_I2C_DEV" default="TRUE" case="upper|lower"/>
     <define name="USE_$(MAG_HMC58XX_I2C_DEV_UPPER)"/>
     <define name="MAG_HMC58XX_I2C_DEV" value="$(MAG_HMC58XX_I2C_DEV_LOWER)"/>
   </makefile>
diff --git a/conf/modules/mavlink.xml b/conf/modules/mavlink.xml
index d2d9ee6a75..6cfb20d605 100644
--- a/conf/modules/mavlink.xml
+++ b/conf/modules/mavlink.xml
@@ -20,10 +20,8 @@
     <file name="mission_manager.c" dir="modules/datalink/missionlib"/>
     <file name="waypoints.c" dir="modules/datalink/missionlib"/>
     <file name="blocks.c" dir="modules/datalink/missionlib"/>
+    <configure name="MAVLINK_PORT" value="uart1" default="TRUE" case="upper|lower"/>
     <raw>
-      MAVLINK_PORT ?= UART1
-      MAVLINK_PORT_UPPER=$(shell echo $(MAVLINK_PORT) | tr a-z A-Z)
-      MAVLINK_PORT_LOWER=$(shell echo $(MAVLINK_PORT) | tr A-Z a-z)
       ifneq (,$(findstring usb,$(MAVLINK_PORT_LOWER)))
       ap.CFLAGS += -DUSE_USB_SERIAL
       ap.srcs += $(SRC_ARCH)/usb_ser_hw.c
diff --git a/conf/modules/mavlink_decoder.xml b/conf/modules/mavlink_decoder.xml
index 18182e7c27..dc247aa7a6 100644
--- a/conf/modules/mavlink_decoder.xml
+++ b/conf/modules/mavlink_decoder.xml
@@ -11,12 +11,10 @@
   </header>
   <event fun="MavlinkDatalinkEvent()"/>
   <makefile>
-    <raw>
-      MAVLINK_PORT_LOWER=$(shell echo $(MAVLINK_PORT) | tr A-Z a-z)
-    </raw>
+    <configure name="MAVLINK_PORT" case="upper|lower"/>
     <define name="MAVLINK_UART" value="$(MAVLINK_PORT_LOWER)"/>
-    <define name="USE_$(MAVLINK_PORT)"/>
-    <define name="$(MAVLINK_PORT)_BAUD" value="$(MAVLINK_BAUD)"/>
+    <define name="USE_$(MAVLINK_PORT_UPPER)"/>
+    <define name="$(MAVLINK_PORT_UPPER)_BAUD" value="$(MAVLINK_BAUD)"/>
     <file name="mavlink_decoder.c"/>
   </makefile>
 </module>
diff --git a/conf/modules/meteo_stick.xml b/conf/modules/meteo_stick.xml
index ac1893158b..e95a66f40f 100644
--- a/conf/modules/meteo_stick.xml
+++ b/conf/modules/meteo_stick.xml
@@ -52,10 +52,7 @@
   <periodic fun="meteo_stick_periodic()" freq="10" autorun="TRUE"/>
   <event fun="meteo_stick_event()"/>
   <makefile target="ap">
-    <raw>
-MS_SPI_DEV_UPPER=$(shell echo $(MS_SPI_DEV) | tr a-z A-Z)
-MS_SPI_DEV_LOWER=$(shell echo $(MS_SPI_DEV) | tr A-Z a-z)
-    </raw>
+    <configure name="MS_SPI_DEV" case="upper|lower"/>
     <file name="meteo_stick.c"/>
     <file name="meteo_stick_calib.c"/>
     <file name="ads1220.c" dir="peripherals"/>
diff --git a/conf/modules/module.dtd b/conf/modules/module.dtd
index 368fce406a..aa65106380 100644
--- a/conf/modules/module.dtd
+++ b/conf/modules/module.dtd
@@ -63,7 +63,9 @@ prefix CDATA #IMPLIED>
 
 <!ATTLIST configure
 name CDATA #REQUIRED
-value CDATA #REQUIRED
+value CDATA #IMPLIED
+case CDATA #IMPLIED
+default CDATA #IMPLIED
 description CDATA #IMPLIED>
 
 <!ATTLIST define
diff --git a/conf/modules/osd_max7456.xml b/conf/modules/osd_max7456.xml
index f4a2e5ecf6..abdca90edf 100644
--- a/conf/modules/osd_max7456.xml
+++ b/conf/modules/osd_max7456.xml
@@ -13,15 +13,9 @@
   <periodic fun="max7456_periodic()" freq="20" autorun="TRUE"/>
   <event fun="max7456_event()"/>
   <makefile target="ap">
+    <configure name="MAX7456_SPI_DEV" value="spi2" default="TRUE" case="upper|lower"/>
+    <configure name="MAX7456_SLAVE_IDX" value="spi_slave2" default="TRUE" case="upper|lower"/>
     <raw>
-      MAX7456_SPI_DEV ?= spi2
-      MAX7456_SPI_DEV_LOWER=$(shell echo $(MAX7456_SPI_DEV) | tr A-Z a-z)
-      MAX7456_SPI_DEV_UPPER=$(shell echo $(MAX7456_SPI_DEV) | tr a-z A-Z)
-
-      MAX7456_SLAVE_IDX ?= spi_slave2
-      MAX7456_SLAVE_IDX_LOWER=$(shell echo $(MAX7456_SLAVE_IDX) | tr A-Z a-z)
-      MAX7456_SLAVE_IDX_UPPER=$(shell echo $(MAX7456_SLAVE_IDX) | tr a-z A-Z)
-
       include $(CFG_SHARED)/spi_master.makefile
     </raw>
     <define name="USE_$(MAX7456_SPI_DEV_UPPER)" />
diff --git a/conf/modules/stereocam.xml b/conf/modules/stereocam.xml
index d849aa59ca..b1ab587e45 100644
--- a/conf/modules/stereocam.xml
+++ b/conf/modules/stereocam.xml
@@ -20,10 +20,7 @@
   <periodic fun="stereocam_periodic()" start="stereocam_start()" stop="stereocam_stop()" autorun="TRUE" freq="512"/>
   <makefile>
     <file name="stereoprotocol.c" dir="modules/stereocam"/>
-    <raw>
-      STEREO_UART_LOWER=$(shell echo $(STEREO_UART) | tr A-Z a-z)
-      STEREO_UART_UPPER=$(shell echo $(STEREO_UART) | tr a-z A-Z)
-    </raw>
+    <configure name="STEREO_UART" case="upper|lower"/>
     <define name="USE_$(STEREO_UART_UPPER)"/>
     <define name="UART_LINK" value="$(STEREO_UART_LOWER)"/>
     <define name="$(STEREO_UART_UPPER)_BAUD" value="$(STEREO_BAUD)"/>
diff --git a/conf/modules/stereocam_droplet.xml b/conf/modules/stereocam_droplet.xml
index 91e12b933c..7cea059ccf 100644
--- a/conf/modules/stereocam_droplet.xml
+++ b/conf/modules/stereocam_droplet.xml
@@ -11,15 +11,12 @@
   <periodic fun="stereocam_droplet_periodic()" freq="20" autorun="TRUE"/>
   <makefile target="ap">
     <file name="droplet/stereocam_droplet.c"/>
-    <raw>
-      STEREO_UART ?= UART1
-      STEREO_BAUD ?= B9600
-      STEREO_LED ?= 3
-      STEREO_UART_LOWER=$(shell echo $(STEREO_UART) | tr A-Z a-z)
-    </raw>
-    <define name="USE_$(STEREO_UART)"/>
+    <configure name="STEREO_UART" value="uart1" default="TRUE" case="upper|lower"/>
+    <configure name="STEREO_BAUD" value="B9600" default="TRUE"/>
+    <configure name="STEREO_LED" value="3" default="TRUE"/>
+    <define name="USE_$(STEREO_UART_UPPER)"/>
     <define name="STEREO_UART" value="$(STEREO_UART_LOWER)"/>
-    <define name="$(STEREO_UART)_BAUD" value="$(STEREO_BAUD)"/>
+    <define name="$(STEREO_UART_UPPER)_BAUD" value="$(STEREO_BAUD)"/>
   </makefile>
 </module>
 
diff --git a/conf/modules/stereocam_nav_line_avoid.xml b/conf/modules/stereocam_nav_line_avoid.xml
index 1ca37ca6d7..09b8790d9e 100644
--- a/conf/modules/stereocam_nav_line_avoid.xml
+++ b/conf/modules/stereocam_nav_line_avoid.xml
@@ -14,15 +14,12 @@
   <periodic fun="stereo_avoid_run()" freq="20" autorun="TRUE"/>
 
   <makefile>
-    <raw>
-      STEREO_UART ?= UART1
-      STEREO_BAUD ?= B9600
-      STEREO_LED ?= 3
-      STEREO_UART_LOWER=$(shell echo $(STEREO_UART) | tr A-Z a-z)
-    </raw>
-    <define name="USE_$(STEREO_UART)"/>
+    <configure name="STEREO_UART" value="uart1" default="TRUE" case="upper|lower"/>
+    <configure name="STEREO_BAUD" value="B9600" default="TRUE"/>
+    <configure name="STEREO_LED" value="3" default="TRUE"/>
+    <define name="USE_$(STEREO_UART_UPPER)"/>
     <define name="STEREO_UART" value="$(STEREO_UART_LOWER)"/>
-    <define name="$(STEREO_UART)_BAUD" value="$(STEREO_BAUD)"/>
+    <define name="$(STEREO_UART_UPPER)_BAUD" value="$(STEREO_BAUD)"/>
     <file name="nav_line_avoid/avoid_navigation.c"/>
   </makefile>
   <makefile  target="ap">
diff --git a/conf/modules/stereocam_state2camera.xml b/conf/modules/stereocam_state2camera.xml
index bb03d1b4f2..f40a4511a6 100644
--- a/conf/modules/stereocam_state2camera.xml
+++ b/conf/modules/stereocam_state2camera.xml
@@ -17,12 +17,10 @@
   <makefile>
     <file name="state2camera/state2camera.c"/>
     <file name="stereoprotocol.c" dir="modules/stereocam"/>
-    <raw>
-        STEREO_UART_LOWER=$(shell echo $(STEREO_UART) | tr A-Z a-z)
-        ap.CFLAGS += -DUSE_$(STEREO_UART)
-        ap.CFLAGS += -DUART_LINK=$(STEREO_UART_LOWER)
-        ap.CFLAGS += -D$(STEREO_UART)_BAUD=$(STEREO_BAUD)
-    </raw>
+    <configure name="STEREO_UART" case="upper|lower"/>
+    <define name="USE_$(STEREO_UART_UPPER)"/>
+    <define name="UART_LINK" value="$(STEREO_UART_LOWER)"/>
+    <define name="$(STEREO_UART_UPPER)_BAUD" value="$(STEREO_BAUD)"/>
   </makefile>
 
 </module>
diff --git a/conf/modules/temp_temod.xml b/conf/modules/temp_temod.xml
index f80f626a86..d0f9fec30d 100644
--- a/conf/modules/temp_temod.xml
+++ b/conf/modules/temp_temod.xml
@@ -14,11 +14,7 @@
   <periodic fun="temod_periodic()" freq="8"/>
   <event fun="temod_event()"/>
   <makefile target="ap">
-     <raw>
-      TEMOD_I2C_DEV ?= i2c0
-      TEMOD_I2C_DEV_LOWER=$(shell echo $(TEMOD_I2C_DEV) | tr A-Z a-z)
-      TEMOD_I2C_DEV_UPPER=$(shell echo $(TEMOD_I2C_DEV) | tr a-z A-Z)
-    </raw>
+    <configure name="TEMOD_I2C_DEV" value="i2c0" default="TRUE" case="upper|lower"/>
     <define name="USE_$(TEMOD_I2C_DEV_UPPER)"/>
     <define name="TEMOD_I2C_DEV" value="$(TEMOD_I2C_DEV_LOWER)"/>
     <file name="temp_temod.c"/>
diff --git a/conf/modules/uart_drop.xml b/conf/modules/uart_drop.xml
index cb86abcbd4..6443cd47d5 100644
--- a/conf/modules/uart_drop.xml
+++ b/conf/modules/uart_drop.xml
@@ -9,12 +9,11 @@
   </header>
   <makefile>
     <file name="uart_drop.c"/>
-    <raw>
-      UART_DROP_PORT ?= UART1
-      UART_DROP_BAUD ?= B115200
-      UART_DROP_PORT_LOWER = $(shell echo $(UART_DROP_PORT) | tr A-Z a-z)
-      ap.CFLAGS += -DUART_DROP_PORT=$(UART_DROP_PORT_LOWER) -DUSE_$(UART_DROP_PORT) -D$(UART_DROP_PORT)_BAUD=$(UART_DROP_BAUD)
-    </raw>
+    <configure name="UART_DROP_PORT" value="uart1" default="TRUE" case="upper|lower"/>
+    <configure name="UART_DROP_BAUD" value="B115200" default="TRUE"/>
+    <define name="UART_DROP_PORT" value="$(UART_DROP_PORT_LOWER)"/>
+    <define name="USE_$(UART_DROP_PORT_UPPER)"/>
+    <define name="$(UART_DROP_PORT_UPPER)_BAUD" value="$(UART_DROP_BAUD)"/>
   </makefile>
 </module>
 
diff --git a/sw/tools/generators/gen_aircraft.ml b/sw/tools/generators/gen_aircraft.ml
index b4e109fcfa..4af126f821 100644
--- a/sw/tools/generators/gen_aircraft.ml
+++ b/sw/tools/generators/gen_aircraft.ml
@@ -54,10 +54,22 @@ let check_unique_id_and_name = fun conf conf_xml ->
       Hashtbl.add names name id
     ) conf
 
+
 let configure_xml2mk = fun f xml ->
+  (* all makefiles variables are forced to uppercase *)
   let name = String.uppercase (ExtXml.attrib xml "name")
-  and value = ExtXml.attrib xml "value" in
-  fprintf f "%s = %s\n" name value
+  and value = ExtXml.attrib_or_default xml "value" ""
+  and default = if String.lowercase (ExtXml.attrib_or_default xml "default" "") = "true" then "?" else ""
+  and case = ExtXml.attrib_or_default xml "case" "" in
+  (* Only print variable if value is not empty *)
+  if String.length value > 0 then
+    fprintf f "%s =%s %s\n" name default value;
+  (* also providing lower and upper case version on request *)
+  if Str.string_match (Str.regexp ".*lower.*") case 0 then
+    fprintf f "%s_LOWER = $(shell echo $(%s) | tr A-Z a-z)\n" name name;
+  if Str.string_match (Str.regexp ".*upper.*") case 0 then
+    fprintf f "%s_UPPER = $(shell echo $(%s) | tr a-z A-Z)\n" name name
+  
 
 let define_xml2mk = fun f ?(target="$(TARGET)") ?(vpath=None) xml ->
   let name = Xml.attrib xml "name"