diff --git a/Makefile b/Makefile
index ebf45b515..f0e7e9720 100644
--- a/Makefile
+++ b/Makefile
@@ -267,6 +267,7 @@ $(1): fw_$(1)_opfw
 fw_$(1): fw_$(1)_opfw
 
 fw_$(1)_%: uavobjects_flight
+	$(V1) $$(ARM_GCC_VERSION_CHECK_TEMPLATE)
 	$(V1) $(MKDIR) -p $(BUILD_DIR)/fw_$(1)/dep
 	$(V1) cd $(ROOT_DIR)/flight/targets/$(2) && \
 		$$(MAKE) -r --no-print-directory \
@@ -294,6 +295,7 @@ bl_$(1): bl_$(1)_bin
 bl_$(1)_bino: bl_$(1)_bin
 
 bl_$(1)_%:
+	$(V1) $$(ARM_GCC_VERSION_CHECK_TEMPLATE)
 	$(V1) $(MKDIR) -p $(BUILD_DIR)/bl_$(1)/dep
 	$(V1) cd $(ROOT_DIR)/flight/targets/Bootloaders/$(2) && \
 		$$(MAKE) -r --no-print-directory \
diff --git a/flight/Modules/Attitude/attitude.c b/flight/Modules/Attitude/attitude.c
index b65811069..6bc72e8c9 100644
--- a/flight/Modules/Attitude/attitude.c
+++ b/flight/Modules/Attitude/attitude.c
@@ -218,14 +218,14 @@ static void AttitudeTask(void *parameters)
 			// For first 7 seconds use accels to get gyro bias
 			accelKp = 1;
 			accelKi = 0.9;
-			yawBiasRate = 0.23;
+			yawBiasRate = 0.01;
 			accel_filter_enabled = false;
 			init = 0;
 		}
 		else if (zero_during_arming && (flightStatus.Armed == FLIGHTSTATUS_ARMED_ARMING)) {
 			accelKp = 1;
 			accelKi = 0.9;
-			yawBiasRate = 0.23;
+			yawBiasRate = 0.01;
 			accel_filter_enabled = false;
 			init = 0;
 		} else if (init == 0) {
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/ground/openpilotgcs/openpilotgcs.pro b/ground/openpilotgcs/openpilotgcs.pro
index 57a5f1ecf..de158d9eb 100644
--- a/ground/openpilotgcs/openpilotgcs.pro
+++ b/ground/openpilotgcs/openpilotgcs.pro
@@ -4,9 +4,9 @@
 #
 
 #version check qt
-contains(QT_VERSION, ^4\\.[0-5]\\..*) {
+contains(QT_VERSION, ^4\\.[0-7]\\..*) {
     message("Cannot build OpenPilot GCS with Qt version $${QT_VERSION}.")
-    error("Cannot build OpenPilot GCS with Qt version $${QT_VERSION}. Use at least Qt 4.6!")
+    error("Cannot build OpenPilot GCS with Qt version $${QT_VERSION}. Use at least Qt 4.8!")
 }
 
 include(openpilotgcs.pri)
diff --git a/ground/openpilotgcs/src/app/gcsversioninfo.pri b/ground/openpilotgcs/src/app/gcsversioninfo.pri
index 0dbf3e19e..cc1d9c629 100644
--- a/ground/openpilotgcs/src/app/gcsversioninfo.pri
+++ b/ground/openpilotgcs/src/app/gcsversioninfo.pri
@@ -5,14 +5,37 @@
 # the other dependencies evaluation.
 #
 
+# We use python to extract git version info, but it may be installed locally.
+# This expected python version should be kept in sync with make/tools.mk.
+PYTHON_DIR = python-2.7.4
+
 # Since debug_and_release option is set, we need this
 !debug_and_release|build_pass {
-    ROOT_DIR              = $$GCS_SOURCE_TREE/../..
+
+    ROOT_DIR = $$GCS_SOURCE_TREE/../..
+
+    # Search the python using environment override first
+    OPENPILOT_TOOLS_DIR = $$(OPENPILOT_TOOLS_DIR)
+    !isEmpty(OPENPILOT_TOOLS_DIR):exists($$OPENPILOT_TOOLS_DIR/$$PYTHON_DIR/python*) {
+        PYTHON = \"$$OPENPILOT_TOOLS_DIR/$$PYTHON_DIR/python\"
+    } else {
+        # If not found, search the predefined tools path
+        exists($$ROOT_DIR/tools/$$PYTHON_DIR/python*) {
+            PYTHON = \"$$ROOT_DIR/tools/$$PYTHON_DIR/python\"
+        } else {
+            # not found, hope it's in the path...
+            PYTHON = \"python\"
+        }
+    }
+    PYTHON = $$replace(PYTHON, \\\\, /)
+    message(Using python interpreter: $$PYTHON)
+
+    # Define other variables
     VERSION_INFO_DIR      = $$GCS_BUILD_TREE/../openpilotgcs-synthetics
     VERSION_INFO_HEADER   = $$VERSION_INFO_DIR/gcs_version_info.h
     VERSION_INFO_SCRIPT   = $$ROOT_DIR/make/scripts/version-info.py
     VERSION_INFO_TEMPLATE = $$ROOT_DIR/make/templates/gcs_version_info_template.h
-    VERSION_INFO_COMMAND  = python \"$$VERSION_INFO_SCRIPT\"
+    VERSION_INFO_COMMAND  = $$PYTHON \"$$VERSION_INFO_SCRIPT\"
     UAVO_DEF_PATH         = $$ROOT_DIR/shared/uavobjectdefinition
 
     # Create custom version_info target which generates a header
diff --git a/make/apps-defs.mk b/make/apps-defs.mk
index 20bb858c0..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.
@@ -175,3 +175,6 @@ ifeq ($(MCU),cortex-m3)
 else ifeq ($(MCU),cortex-m4)
     LDFLAGS += $(addprefix -T,$(LINKER_SCRIPTS_APP))
 endif
+
+# Add jtag targets (program and wipe)
+$(eval $(call JTAG_TEMPLATE,$(OUTDIR)/$(TARGET).bin,$(FW_BANK_BASE),$(FW_BANK_SIZE),$(OPENOCD_JTAG_CONFIG),$(OPENOCD_CONFIG)))
diff --git a/make/boot-defs.mk b/make/boot-defs.mk
index 13db9ab17..ae311faa7 100644
--- a/make/boot-defs.mk
+++ b/make/boot-defs.mk
@@ -123,3 +123,6 @@ ifeq ($(MCU),cortex-m3)
 else ifeq ($(MCU),cortex-m4)
     LDFLAGS += $(addprefix -T,$(LINKER_SCRIPTS_BL))
 endif
+
+# Add jtag targets (program and wipe)
+$(eval $(call JTAG_TEMPLATE,$(OUTDIR)/$(TARGET).bin,$(BL_BANK_BASE),$(BL_BANK_SIZE),$(OPENOCD_JTAG_CONFIG),$(OPENOCD_CONFIG)))
diff --git a/make/common-defs.mk b/make/common-defs.mk
index de86b0542..4af7e3dc2 100644
--- a/make/common-defs.mk
+++ b/make/common-defs.mk
@@ -229,13 +229,10 @@ $(eval $(call PARTIAL_COMPILE_TEMPLATE, SRC))
 # Compile: create assembler files from C source files. ARM only
 $(eval $(call PARTIAL_COMPILE_ARM_TEMPLATE, SRCARM))
 
-$(OUTDIR)/$(TARGET).bin.o: $(OUTDIR)/$(TARGET).bin
-
 # Add opfw target
 $(eval $(call OPFW_TEMPLATE,$(OUTDIR)/$(TARGET).bin,$(BOARD_TYPE),$(BOARD_REVISION)))
 
-# Add jtag targets (program and wipe)
-$(eval $(call JTAG_TEMPLATE,$(OUTDIR)/$(TARGET).bin,$(BL_BANK_BASE),$(BL_BANK_SIZE),$(OPENOCD_JTAG_CONFIG),$(OPENOCD_CONFIG)))
+$(OUTDIR)/$(TARGET).bin.o: $(OUTDIR)/$(TARGET).bin
 
 .PHONY: elf lss sym hex bin bino opfw
 elf: $(OUTDIR)/$(TARGET).elf
diff --git a/make/tools.mk b/make/tools.mk
index c1d97e741..e15d2a69f 100644
--- a/make/tools.mk
+++ b/make/tools.mk
@@ -52,15 +52,16 @@ endif
 ##############################
 
 ifeq ($(UNAME), Linux)
-    ARM_SDK_URL := http://wiki.openpilot.org/download/attachments/18612236/gcc-arm-none-eabi-4_7-2013q1-20130313-linux.tar.bz2
     ifeq ($(ARCH), x86_64)
-        QT_SDK_URL  := http://wiki.openpilot.org/download/attachments/18612236/qt-4.8.4-linux-x64.tar.bz2
+        ARM_SDK_URL := http://wiki.openpilot.org/download/attachments/18612236/gcc-arm-none-eabi-4_7-2013q1-20130313-linux-amd64.tar.bz2
+        QT_SDK_URL  := "Please install native Qt 4.8.x SDK using package manager"
     else
-        QT_SDK_URL  := http://wiki.openpilot.org/download/attachments/18612236/qt-4.8.4-linux.tar.bz2
+        ARM_SDK_URL := http://wiki.openpilot.org/download/attachments/18612236/gcc-arm-none-eabi-4_7-2013q1-20130313-linux-i686.tar.bz2
+        QT_SDK_URL  := "Please install native Qt 4.8.x SDK using package manager"
     endif
 else ifeq ($(UNAME), Darwin)
     ARM_SDK_URL := http://wiki.openpilot.org/download/attachments/18612236/gcc-arm-none-eabi-4_7-2013q1-20130313-mac.tar.bz2
-    QT_SDK_URL  := TODO/qt-4.8.4-mac.tar.bz2
+    QT_SDK_URL  := "Please install native Qt 4.8.x SDK using package manager"
 else ifeq ($(UNAME), Windows)
     ARM_SDK_URL := http://wiki.openpilot.org/download/attachments/18612236/gcc-arm-none-eabi-4_7-2013q1-20130313-windows.tar.bz2
     QT_SDK_URL  := http://wiki.openpilot.org/download/attachments/18612236/qt-4.8.4-windows.tar.bz2
@@ -68,6 +69,7 @@ else ifeq ($(UNAME), Windows)
     PYTHON_URL  := http://wiki.openpilot.org/download/attachments/18612236/python-2.7.4-windows.tar.bz2
 endif
 
+# Changing PYTHON_DIR, also update it in ground\openpilotgcs\src\app\gcsversioninfo.pri
 ARM_SDK_DIR     := $(TOOLS_DIR)/gcc-arm-none-eabi-4_7-2013q1
 QT_SDK_DIR      := $(TOOLS_DIR)/qt-4.8.4
 MINGW_DIR       := $(TOOLS_DIR)/mingw-4.4.0
@@ -239,6 +241,15 @@ endif
 arm_sdk_version:
 	$(V1) $(ARM_SDK_PREFIX)gcc --version | head -n1
 
+# Template to check ARM toolchain version before building targets
+define ARM_GCC_VERSION_CHECK_TEMPLATE
+	if ! $(ARM_SDK_PREFIX)gcc --version --specs=nano.specs >/dev/null 2>&1; then \
+		$(ECHO) $(MSG_NOTICE) Please install ARM toolchain 4.7+ using \'make arm_sdk_install\' && \
+		$(ECHO) $(MSG_NOTICE) Older ARM SDKs do not support new \'--specs=nano.specs\' option && \
+		exit 1; \
+	fi
+endef
+
 ##############################
 #
 # Qt SDK
diff --git a/package/linux/deb_common/postinst b/package/linux/deb_common/postinst
index df8022075..e58a3e1a3 100644
--- a/package/linux/deb_common/postinst
+++ b/package/linux/deb_common/postinst
@@ -20,7 +20,7 @@ set -e
 
 case "$1" in
     configure)
-        sudo udevadm control --reload-rules >&2
+        /sbin/udevadm control --reload-rules >&2
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)