diff --git a/flight/PiOS/Common/Libraries/CMSIS2/library.mk b/flight/PiOS/Common/Libraries/CMSIS2/library.mk
index fd9410ad0..e7d8e8572 100644
--- a/flight/PiOS/Common/Libraries/CMSIS2/library.mk
+++ b/flight/PiOS/Common/Libraries/CMSIS2/library.mk
@@ -11,7 +11,7 @@ ifeq ($(USE_DSP_LIB), YES)
     CMSIS_DSPLIB	:= $(CMSIS2_DIR)DSP_Lib/Source
 
     # Compile all files into output directory
-    DSPLIB_SRC		:= $(wildcard $(CMSIS_DSPLIB)/*/*.c)
+    DSPLIB_SRC		:= $(sort $(wildcard $(CMSIS_DSPLIB)/*/*.c))
     DSPLIB_SRCBASE	:= $(notdir $(basename $(DSPLIB_SRC)))
     $(foreach src, $(DSPLIB_SRC), $(eval $(call COMPILE_C_TEMPLATE, $(src))))
 
diff --git a/flight/PiOS/Common/Libraries/FreeRTOS/library.mk b/flight/PiOS/Common/Libraries/FreeRTOS/library.mk
index 9e101b273..70005c3c6 100644
--- a/flight/PiOS/Common/Libraries/FreeRTOS/library.mk
+++ b/flight/PiOS/Common/Libraries/FreeRTOS/library.mk
@@ -6,5 +6,5 @@
 #
 
 FREERTOS_DIR	:= $(dir $(lastword $(MAKEFILE_LIST)))/Source
-SRC		+= $(wildcard $(FREERTOS_DIR)/*.c)
+SRC		+= $(sort $(wildcard $(FREERTOS_DIR)/*.c))
 EXTRAINCDIRS	+= $(FREERTOS_DIR)/include
diff --git a/flight/PiOS/Common/Libraries/dosfs/library.mk b/flight/PiOS/Common/Libraries/dosfs/library.mk
index 0e6fa982e..4b8499788 100644
--- a/flight/PiOS/Common/Libraries/dosfs/library.mk
+++ b/flight/PiOS/Common/Libraries/dosfs/library.mk
@@ -3,5 +3,5 @@
 #
 
 DOSFS_DIR	:= $(dir $(lastword $(MAKEFILE_LIST)))
-SRC		+= $(wildcard $(DOSFS_DIR)*.c)
+SRC		+= $(sort $(wildcard $(DOSFS_DIR)*.c))
 EXTRAINCDIRS	+= $(DOSFS_DIR)
diff --git a/flight/PiOS/Common/Libraries/msheap/library.mk b/flight/PiOS/Common/Libraries/msheap/library.mk
index 84a796e62..80a8b7e25 100644
--- a/flight/PiOS/Common/Libraries/msheap/library.mk
+++ b/flight/PiOS/Common/Libraries/msheap/library.mk
@@ -3,5 +3,5 @@
 #
 
 MSHEAP_DIR	:= $(dir $(lastword $(MAKEFILE_LIST)))
-SRC		+= $(wildcard $(MSHEAP_DIR)*.c)
+SRC		+= $(sort $(wildcard $(MSHEAP_DIR)*.c))
 EXTRAINCDIRS	+= $(MSHEAP_DIR)
diff --git a/flight/PiOS/STM32F10x/library.mk b/flight/PiOS/STM32F10x/library.mk
index df95cfc72..d0d5a0809 100644
--- a/flight/PiOS/STM32F10x/library.mk
+++ b/flight/PiOS/STM32F10x/library.mk
@@ -18,7 +18,7 @@ ARCHFLAGS		+= -mcpu=cortex-m3 --specs=nano.specs
 ASRC			+= $(PIOS_DEVLIB)startup_stm32f10x_$(MODEL)$(MODEL_SUFFIX).S
 
 # PIOS device library source and includes
-SRC			+= $(wildcard $(PIOS_DEVLIB)*.c)
+SRC			+= $(sort $(wildcard $(PIOS_DEVLIB)*.c))
 
 # CMSIS for the F1
 include $(PIOS)/Common/Libraries/CMSIS2/library.mk
@@ -29,12 +29,12 @@ EXTRAINCDIRS		+= $(CMSIS_DIR)
 
 # ST Peripheral library
 PERIPHLIB		=  $(PIOS_DEVLIB)Libraries/STM32F10x_StdPeriph_Driver
-SRC			+= $(wildcard $(PERIPHLIB)/src/*.c)
+SRC			+= $(sort $(wildcard $(PERIPHLIB)/src/*.c))
 EXTRAINCDIRS		+= $(PERIPHLIB)/inc
 
 # ST USB Device library
 USBDEVLIB		=  $(PIOS_DEVLIB)Libraries/STM32_USB-FS-Device_Driver
-SRC			+= $(wildcard $(USBDEVLIB)/src/*.c)
+SRC			+= $(sort $(wildcard $(USBDEVLIB)/src/*.c))
 EXTRAINCDIRS		+= $(USBDEVLIB)/inc
 
 #
@@ -45,7 +45,7 @@ EXTRAINCDIRS		+= $(USBDEVLIB)/inc
 #
 ifneq ($(FREERTOS_DIR),)
     FREERTOS_PORTDIR	:= $(PIOS_DEVLIB)Libraries/FreeRTOS/Source
-    SRC			+= $(wildcard $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM3/*.c)
-    SRC			+= $(wildcard $(FREERTOS_PORTDIR)/portable/MemMang/heap_1.c)
+    SRC			+= $(sort $(wildcard $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM3/*.c))
+    SRC			+= $(sort $(wildcard $(FREERTOS_PORTDIR)/portable/MemMang/heap_1.c))
     EXTRAINCDIRS	+= $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM3
 endif
diff --git a/flight/PiOS/STM32F4xx/library.mk b/flight/PiOS/STM32F4xx/library.mk
index 531dbbfb2..a38b2720d 100644
--- a/flight/PiOS/STM32F4xx/library.mk
+++ b/flight/PiOS/STM32F4xx/library.mk
@@ -20,18 +20,18 @@ CDEFS			+= -DARM_MATH_CM4 -D__FPU_PRESENT=1
 ARCHFLAGS		+= -mcpu=cortex-m4 -march=armv7e-m -mfpu=fpv4-sp-d16 -mfloat-abi=hard
 
 # PIOS device library source and includes
-SRC			+= $(wildcard $(PIOS_DEVLIB)*.c)
+SRC			+= $(sort $(wildcard $(PIOS_DEVLIB)*.c))
 EXTRAINCDIRS		+= $(PIOS_DEVLIB)inc
 
 # CMSIS for the F4
 include $(PIOSCOMMON)/Libraries/CMSIS2/library.mk
 CMSIS2_DEVICEDIR	:= $(PIOS_DEVLIB)Libraries/CMSIS2/Device/ST/STM32F4xx
-SRC			+= $(wildcard $(CMSIS2_DEVICEDIR)/Source/$(BOARD_NAME)/*.c)
+SRC			+= $(sort $(wildcard $(CMSIS2_DEVICEDIR)/Source/$(BOARD_NAME)/*.c))
 EXTRAINCDIRS		+= $(CMSIS2_DEVICEDIR)/Include
 
 # ST Peripheral library
 PERIPHLIB		=  $(PIOS_DEVLIB)Libraries/STM32F4xx_StdPeriph_Driver
-SRC			+= $(wildcard $(PERIPHLIB)/src/*.c)
+SRC			+= $(sort $(wildcard $(PERIPHLIB)/src/*.c))
 EXTRAINCDIRS		+= $(PERIPHLIB)/inc
 
 # ST USB OTG library
@@ -42,7 +42,7 @@ EXTRAINCDIRS		+= $(USBOTGLIB)/inc
 
 # ST USB Device library
 USBDEVLIB		=  $(PIOS_DEVLIB)Libraries/STM32_USB_Device_Library
-SRC			+= $(wildcard $(USBDEVLIB)/Core/src/*.c)
+SRC			+= $(sort $(wildcard $(USBDEVLIB)/Core/src/*.c))
 EXTRAINCDIRS		+= $(USBDEVLIB)/Core/inc
 
 #
@@ -53,7 +53,7 @@ EXTRAINCDIRS		+= $(USBDEVLIB)/Core/inc
 #
 ifneq ($(FREERTOS_DIR),)
     FREERTOS_PORTDIR	:= $(PIOS_DEVLIB)Libraries/FreeRTOS/Source
-    SRC			+= $(wildcard $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM4F/*.c)
+    SRC			+= $(sort $(wildcard $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM4F/*.c))
     EXTRAINCDIRS	+= $(FREERTOS_PORTDIR)/portable/GCC/ARM_CM4F
     include $(PIOSCOMMON)/Libraries/msheap/library.mk
 endif
diff --git a/flight/PiOS/posix/Libraries/FreeRTOS/library.mk b/flight/PiOS/posix/Libraries/FreeRTOS/library.mk
index c6267255f..08381319f 100644
--- a/flight/PiOS/posix/Libraries/FreeRTOS/library.mk
+++ b/flight/PiOS/posix/Libraries/FreeRTOS/library.mk
@@ -6,5 +6,5 @@
 #
 
 FREERTOS_DIR	:=	$(dir $(lastword $(MAKEFILE_LIST)))/Source
-SRC		+=	$(wildcard $(FREERTOS_DIR)/*.c)
+SRC		+=	$(sort $(wildcard $(FREERTOS_DIR)/*.c))
 EXTRAINCDIRS	+=	$(FREERTOS_DIR)/include
diff --git a/flight/PiOS/posix/library.mk b/flight/PiOS/posix/library.mk
index 530431210..79cadc5c7 100644
--- a/flight/PiOS/posix/library.mk
+++ b/flight/PiOS/posix/library.mk
@@ -27,7 +27,7 @@ ARCHFLAGS			+= -DARCH_POSIX
 #
 # PIOS device library source and includes
 #
-SRC					+=	$(wildcard $(PIOS_DEVLIB)*.c)
+SRC					+=	$(sort $(wildcard $(PIOS_DEVLIB)*.c))
 EXTRAINCDIRS		+=	$(PIOS_DEVLIB)/inc
 
 #
@@ -68,8 +68,8 @@ EXTRAINCDIRS		+=	$(PIOS_DEVLIB)/inc
 #
 ifneq ($(FREERTOS_DIR),)
 FREERTOS_PORTDIR	:=	$(PIOS_DEVLIB)/Libraries/FreeRTOS/Source
-SRC					+=	$(wildcard $(FREERTOS_PORTDIR)/portable/GCC/Posix/*.c)
-SRC					+=	$(wildcard $(FREERTOS_PORTDIR)/portable/MemMang/*.c)
+SRC					+=	$(sort $(wildcard $(FREERTOS_PORTDIR)/portable/GCC/Posix/*.c))
+SRC					+=	$(sort $(wildcard $(FREERTOS_PORTDIR)/portable/MemMang/*.c))
 
 EXTRAINCDIRS		+=	$(FREERTOS_PORTDIR)/portable/GCC/Posix
 endif
diff --git a/make/apps-defs.mk b/make/apps-defs.mk
index e8ff9a016..1f23dc493 100644
--- a/make/apps-defs.mk
+++ b/make/apps-defs.mk
@@ -101,8 +101,8 @@ SRC += $(MATHLIB)/sin_lookup.c
 SRC += $(MATHLIB)/pid.c
 
 ## Modules
-SRC += $(foreach mod, $(MODULES), $(wildcard $(OPMODULEDIR)/$(mod)/*.c))
-SRC += $(foreach mod, $(OPTMODULES), $(wildcard $(OPMODULEDIR)/$(mod)/*.c))
+SRC += $(foreach mod, $(MODULES), $(sort $(wildcard $(OPMODULEDIR)/$(mod)/*.c)))
+SRC += $(foreach mod, $(OPTMODULES), $(sort $(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.