diff --git a/flight/Modules/Airspeed/revolution/airspeed.c b/flight/Modules/Airspeed/revolution/airspeed.c
index ab817232a..fd1479d0f 100644
--- a/flight/Modules/Airspeed/revolution/airspeed.c
+++ b/flight/Modules/Airspeed/revolution/airspeed.c
@@ -89,7 +89,7 @@ int32_t AirspeedStart()
  */
 int32_t AirspeedInitialize()
 {
-#ifdef MODULE_Airspeed_BUILTIN
+#ifdef MODULE_AIRSPEED_BUILTIN
 	airspeedEnabled = true;
 #else
 	
diff --git a/flight/Modules/Altitude/altitude.c b/flight/Modules/Altitude/altitude.c
index 4898829b0..4e11848e7 100644
--- a/flight/Modules/Altitude/altitude.c
+++ b/flight/Modules/Altitude/altitude.c
@@ -92,7 +92,7 @@ int32_t AltitudeStart()
  */
 int32_t AltitudeInitialize()
 {
-#ifdef MODULE_Altitude_BUILTIN
+#ifdef MODULE_ALTITUDE_BUILTIN
 	altitudeEnabled = 1;
 #else
 	HwSettingsInitialize();
diff --git a/flight/Modules/Autotune/autotune.c b/flight/Modules/Autotune/autotune.c
index 366ac190f..260f70750 100644
--- a/flight/Modules/Autotune/autotune.c
+++ b/flight/Modules/Autotune/autotune.c
@@ -82,7 +82,7 @@ static void update_stabilization_settings();
 int32_t AutotuneInitialize(void)
 {
 	// Create a queue, connect to manual control command and flightstatus
-#ifdef MODULE_Autotune_BUILTIN
+#ifdef MODULE_AUTOTUNE_BUILTIN
 	autotuneEnabled = true;
 #else
 	HwSettingsInitialize();
diff --git a/flight/Modules/Battery/battery.c b/flight/Modules/Battery/battery.c
index 83c0002cd..ac9dcace3 100644
--- a/flight/Modules/Battery/battery.c
+++ b/flight/Modules/Battery/battery.c
@@ -78,7 +78,7 @@ int32_t BatteryInitialize(void)
 {
 
 	
-#ifdef MODULE_Battery_BUILTIN
+#ifdef MODULE_BATTERY_BUILTIN
 	batteryEnabled = true;
 #else
 	uint8_t optionalModules[HWSETTINGS_OPTIONALMODULES_NUMELEM];
diff --git a/flight/Modules/CameraStab/camerastab.c b/flight/Modules/CameraStab/camerastab.c
index 12915be68..89f41e821 100644
--- a/flight/Modules/CameraStab/camerastab.c
+++ b/flight/Modules/CameraStab/camerastab.c
@@ -94,7 +94,7 @@ int32_t CameraStabInitialize(void)
 {
 	bool cameraStabEnabled;
 
-#ifdef MODULE_CameraStab_BUILTIN
+#ifdef MODULE_CAMERASTAB_BUILTIN
 	cameraStabEnabled = true;
 #else
 	uint8_t optionalModules[HWSETTINGS_OPTIONALMODULES_NUMELEM];
diff --git a/flight/Modules/ComUsbBridge/ComUsbBridge.c b/flight/Modules/ComUsbBridge/ComUsbBridge.c
index 678e7039d..13c9f6ee4 100644
--- a/flight/Modules/ComUsbBridge/ComUsbBridge.c
+++ b/flight/Modules/ComUsbBridge/ComUsbBridge.c
@@ -94,7 +94,7 @@ static int32_t comUsbBridgeInitialize(void)
 	usart_port = PIOS_COM_BRIDGE;
 	vcp_port = PIOS_COM_VCP;
 
-#ifdef MODULE_ComUsbBridge_BUILTIN
+#ifdef MODULE_COMUSBBRIDGE_BUILTIN
 	bridge_enabled = true;
 #else
 	HwSettingsInitialize();
diff --git a/flight/Modules/Extensions/MagBaro/magbaro.c b/flight/Modules/Extensions/MagBaro/magbaro.c
index e4db11261..ab02a902f 100644
--- a/flight/Modules/Extensions/MagBaro/magbaro.c
+++ b/flight/Modules/Extensions/MagBaro/magbaro.c
@@ -87,7 +87,7 @@ int32_t MagBaroStart()
  */
 int32_t MagBaroInitialize()
 {
-#ifdef MODULE_MagBaro_BUILTIN
+#ifdef MODULE_MAGBARO_BUILTIN
 	magbaroEnabled = 1;
 #else
 	HwSettingsInitialize();
diff --git a/flight/Modules/Fault/Fault.c b/flight/Modules/Fault/Fault.c
index 868330739..b707ed5a5 100644
--- a/flight/Modules/Fault/Fault.c
+++ b/flight/Modules/Fault/Fault.c
@@ -40,7 +40,7 @@ static uint8_t active_fault;
 
 static int32_t fault_initialize(void)
 {
-#ifdef MODULE_Fault_BUILTIN
+#ifdef MODULE_FAULT_BUILTIN
 	module_enabled = true;
 #else
 	HwSettingsInitialize();
diff --git a/flight/Modules/OveroSync/overosync.c b/flight/Modules/OveroSync/overosync.c
index eaa2cb6fb..639082fce 100644
--- a/flight/Modules/OveroSync/overosync.c
+++ b/flight/Modules/OveroSync/overosync.c
@@ -75,7 +75,7 @@ struct overosync *overosync;
 int32_t OveroSyncInitialize(void)
 {
 
-#ifdef MODULE_OveroSync_BUILTIN
+#ifdef MODULE_OVEROSYNC_BUILTIN
 	overoEnabled = true;
 #else
 	
diff --git a/make/apps-defs.mk b/make/apps-defs.mk
index b162a906e..fa368084d 100644
--- a/make/apps-defs.mk
+++ b/make/apps-defs.mk
@@ -104,6 +104,11 @@ SRC += $(MATHLIB)/pid.c
 SRC += $(foreach mod, $(MODULES), $(wildcard $(OPMODULEDIR)/$(mod)/*.c))
 SRC += $(foreach mod, $(OPTMODULES), $(wildcard $(OPMODULEDIR)/$(mod)/*.c))
 
+# Declare all non-optional modules as built-in to force inclusion.
+# Built-in modules are always enabled and cannot be disabled.
+MODULES_BUILTIN := $(foreach mod, $(notdir $(MODULES)), -DMODULE_$(shell $(ECHO) $(mod) | tr '[:lower:]' '[:upper:]')_BUILTIN)
+CDEFS += $(MODULES_BUILTIN)
+
 # List C source files here which must be compiled in ARM-Mode (no -mthumb).
 # Use file-extension c for "c-only"-files
 SRCARM +=
@@ -162,9 +167,6 @@ EXTRA_LIBS += m
 # Compiler flags
 CFLAGS +=
 
-# Declare all non-optional modules as built-in to force inclusion
-CDEFS += $(foreach mod, $(notdir $(MODULES)), -DMODULE_$(mod)_BUILTIN)
-
 # Set linker-script name depending on selected submodel name
 ifeq ($(MCU),cortex-m3)
     LDFLAGS += -T$(LINKER_SCRIPTS_PATH)/link_$(BOARD)_memory.ld