diff --git a/Makefile b/Makefile
index 34a56853ec..14345b960c 100644
--- a/Makefile
+++ b/Makefile
@@ -105,142 +105,17 @@ upload:
 endif
 endif
 
-ifeq ($(PX4_TARGET_OS),nuttx) 
-#
-# Built products
-#
-DESIRED_FIRMWARES 	 = $(foreach config,$(CONFIGS),$(IMAGE_DIR)$(config).px4)
-STAGED_FIRMWARES	 = $(foreach config,$(KNOWN_CONFIGS),$(IMAGE_DIR)$(config).px4)
-FIRMWARES		 = $(foreach config,$(KNOWN_CONFIGS),$(BUILD_DIR)$(config).build/firmware.px4)
-
-all:	$(DESIRED_FIRMWARES)
-
-#
-# Copy FIRMWARES into the image directory.
-#
-# XXX copying the .bin files is a hack to work around the PX4IO uploader
-#     not supporting .px4 files, and it should be deprecated onced that
-#     is taken care of.
-#
-$(STAGED_FIRMWARES): $(IMAGE_DIR)%.px4: $(BUILD_DIR)%.build/firmware.px4
-	@$(ECHO) %% Copying $@
-	$(Q) $(COPY) $< $@
-	$(Q) $(COPY) $(patsubst %.px4,%.bin,$<) $(patsubst %.px4,%.bin,$@)
-
-#
-# Generate FIRMWARES.
-#
-.PHONY: $(FIRMWARES)
-$(BUILD_DIR)%.build/firmware.px4: config   = $(patsubst $(BUILD_DIR)%.build/firmware.px4,%,$@)
-$(BUILD_DIR)%.build/firmware.px4: work_dir = $(BUILD_DIR)$(config).build/
-$(FIRMWARES): $(BUILD_DIR)%.build/firmware.px4:	checkgitversion generateuorbtopicheaders checksubmodules
-	@$(ECHO) %%%%
-	@$(ECHO) %%%% Building $(config) in $(work_dir)
-	@$(ECHO) %%%%
-	$(Q) $(MKDIR) -p $(work_dir)
-	$(Q) $(MAKE) -r -C $(work_dir) \
-		-f $(PX4_MK_DIR)firmware.mk \
-		CONFIG=$(config) \
-		WORK_DIR=$(work_dir) \
-		$(FIRMWARE_GOAL)
-
-#
-# Make FMU firmwares depend on the corresponding IO firmware.
-#
-# This is a pretty vile hack, since it hard-codes knowledge of the FMU->IO dependency
-# and forces the _default config in all cases. There has to be a better way to do this...
-#
-FMU_VERSION		 = $(patsubst px4fmu-%,%,$(word 1, $(subst _, ,$(1))))
-define FMU_DEP
-$(BUILD_DIR)$(1).build/firmware.px4: $(IMAGE_DIR)px4io-$(call FMU_VERSION,$(1))_default.px4
-endef
-FMU_CONFIGS		:= $(filter px4fmu%,$(CONFIGS))
-$(foreach config,$(FMU_CONFIGS),$(eval $(call FMU_DEP,$(config))))
-
-#
-# Build the NuttX export archives.
-#
-# Note that there are no explicit dependencies extended from these
-# archives. If NuttX is updated, the user is expected to rebuild the
-# archives/build area manually. Likewise, when the 'archives' target is
-# invoked, all archives are always rebuilt.
-#
-# XXX Should support fetching/unpacking from a separate directory to permit
-#     downloads of the prebuilt archives as well...
-#
-NUTTX_ARCHIVES		 = $(foreach board,$(BOARDS),$(ARCHIVE_DIR)$(board).export)
-.PHONY:			archives
-archives:		checksubmodules $(NUTTX_ARCHIVES)
-
-# We cannot build these parallel; note that we also force -j1 for the
-# sub-make invocations.
-ifneq ($(filter archives,$(MAKECMDGOALS)),)
-.NOTPARALLEL:
-endif
-
-J?=1
-
-$(ARCHIVE_DIR)%.export:	board = $(notdir $(basename $@))
-$(ARCHIVE_DIR)%.export:	configuration = nsh
-$(NUTTX_ARCHIVES): $(ARCHIVE_DIR)%.export: $(NUTTX_SRC)
-	@$(ECHO) %% Configuring NuttX for $(board)
-	$(Q) (cd $(NUTTX_SRC) && $(RMDIR) nuttx-export)
-	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) distclean
-	$(Q) (cd $(NUTTX_SRC)/configs && $(COPYDIR) $(PX4_BASE)nuttx-configs/$(board) .)
-	$(Q) (cd $(NUTTX_SRC)tools && ./configure.sh $(board)/$(configuration))
-	@$(ECHO) %% Exporting NuttX for $(board)
-	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) CONFIG_ARCH_BOARD=$(board) export
-	$(Q) $(MKDIR) -p $(dir $@)
-	$(Q) $(COPY) $(NUTTX_SRC)nuttx-export.zip $@
-	$(Q) (cd $(NUTTX_SRC)/configs && $(RMDIR) $(board))
-
-#
-# The user can run the NuttX 'menuconfig' tool for a single board configuration with
-# make BOARDS=<boardname> menuconfig
-#
-ifeq ($(MAKECMDGOALS),menuconfig)
-ifneq ($(words $(BOARDS)),1)
-$(error BOARDS must specify exactly one board for the menuconfig goal)
-endif
-BOARD			 = $(BOARDS)
-menuconfig: $(NUTTX_SRC)
-	@$(ECHO) %% Configuring NuttX for $(BOARD)
-	$(Q) (cd $(NUTTX_SRC) && $(RMDIR) nuttx-export)
-	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) distclean
-	$(Q) (cd $(NUTTX_SRC)/configs && $(COPYDIR) $(PX4_BASE)nuttx-configs/$(BOARD) .)
-	$(Q) (cd $(NUTTX_SRC)tools && ./configure.sh $(BOARD)/nsh)
-	@$(ECHO) %% Running menuconfig for $(BOARD)
-	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) oldconfig
-	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) menuconfig
-	@$(ECHO) %% Saving configuration file
-	$(Q)$(COPY) $(NUTTX_SRC).config $(PX4_BASE)nuttx-configs/$(BOARD)/nsh/defconfig
-else
-menuconfig:
-	@$(ECHO) ""
-	@$(ECHO) "The menuconfig goal must be invoked without any other goal being specified"
-	@$(ECHO) ""
-
-endif
-
-$(NUTTX_SRC): checkgitversion checksubmodules
-
-$(UAVCAN_DIR):
-	$(Q) (./Tools/check_submodules.sh)
-
-endif
-
 ifeq ($(PX4_TARGET_OS),nuttx)
-# TODO
-# Move the above nuttx specific rules into $(PX4_BASE)makefiles/firmware_nuttx.mk
+include $(PX4_BASE)makefiles/nuttx/firmware_nuttx.mk
 endif
 ifeq ($(PX4_TARGET_OS),posix)
-include $(PX4_BASE)makefiles/firmware_posix.mk
+include $(PX4_BASE)makefiles/posix/firmware_posix.mk
 endif
 ifeq ($(PX4_TARGET_OS),posix-arm)
-include $(PX4_BASE)makefiles/firmware_posix.mk
+include $(PX4_BASE)makefiles/posix/firmware_posix.mk
 endif
 ifeq ($(PX4_TARGET_OS),qurt)
-include $(PX4_BASE)makefiles/firmware_qurt.mk
+include $(PX4_BASE)makefiles/qurt/firmware_qurt.mk
 endif
 
 #
@@ -409,3 +284,12 @@ endif
 	@$(ECHO) "    If V is set, more verbose output is printed during the build. This can"
 	@$(ECHO) "    help when diagnosing issues with the build or toolchain."
 	@$(ECHO) ""
+ifeq ($(PX4_TARGET_OS),nuttx)
+	@$(ECHO) "  To see help for a specifix target use 'make <target> help' where target is"
+	@$(ECHO) "  one of: "
+	@$(ECHO) "     nuttx"
+	@$(ECHO) "     posix"
+	@$(ECHO) "     qurt"
+	@$(ECHO) ""
+endif
+
diff --git a/makefiles/firmware.mk b/makefiles/firmware.mk
index 43cbfb59c0..bb310dbff5 100644
--- a/makefiles/firmware.mk
+++ b/makefiles/firmware.mk
@@ -101,7 +101,7 @@
 # If PX4_BASE wasn't set previously, work out what it should be
 # and set it here now.
 #
-MK_DIR			?= $(dir $(lastword $(MAKEFILE_LIST)))
+MK_DIR			?= $(dir $(firstword $(MAKEFILE_LIST)))
 ifeq ($(PX4_BASE),)
 export PX4_BASE		:= $(abspath $(MK_DIR)/..)
 endif
@@ -189,7 +189,7 @@ INCLUDE_DIRS		+= $(PX4_MODULE_SRC)drivers/boards/$(BOARD)
 # OS specific libraries and paths
 ################################################################################
 
-include $(PX4_MK_DIR)/$(PX4_TARGET_OS).mk
+include $(PX4_MK_DIR)/$(PX4_TARGET_OS)/$(PX4_TARGET_OS).mk
 
 ################################################################################
 # Modules
@@ -311,131 +311,11 @@ $(LIBRARY_CLEANS):
 	LIBRARY_MK=$(mkfile) \
 	clean
 
-ifeq ($(PX4_TARGET_OS),nuttx)
 ################################################################################
 # ROMFS generation
 ################################################################################
-
-ifneq ($(ROMFS_ROOT),)
-ifeq ($(wildcard $(ROMFS_ROOT)),)
-$(error ROMFS_ROOT specifies a directory that does not exist)
-endif
-
-#
-# Note that there is no support for more than one root directory or constructing
-# a root from several templates. That would be a nice feature.
-#
-
-# Add dependencies on anything in the ROMFS root directory
-ROMFS_FILES		+= $(wildcard \
-			     $(ROMFS_ROOT)/* \
-			     $(ROMFS_ROOT)/*/* \
-			     $(ROMFS_ROOT)/*/*/* \
-			     $(ROMFS_ROOT)/*/*/*/* \
-			     $(ROMFS_ROOT)/*/*/*/*/* \
-			     $(ROMFS_ROOT)/*/*/*/*/*/*)
-ifeq ($(ROMFS_FILES),)
-$(error ROMFS_ROOT $(ROMFS_ROOT) specifies a directory containing no files)
-endif
-ROMFS_DEPS		+= $(ROMFS_FILES)
-
-# Extra files that may be copied into the ROMFS /extras directory
-# ROMFS_EXTRA_FILES are required, ROMFS_OPTIONAL_FILES are optional
-ROMFS_EXTRA_FILES	+= $(wildcard $(ROMFS_OPTIONAL_FILES))
-ROMFS_DEPS		+= $(ROMFS_EXTRA_FILES)
-
-ROMFS_IMG		 = romfs.img
-ROMFS_SCRATCH		 = romfs_scratch
-ROMFS_CSRC		 = $(ROMFS_IMG:.img=.c)
-ROMFS_OBJ		 = $(ROMFS_CSRC:.c=.o)
-LIBS			+= $(ROMFS_OBJ)
-LINK_DEPS		+= $(ROMFS_OBJ)
-
-# Remove all comments from startup and mixer files
-ROMFS_PRUNER	 = $(PX4_BASE)/Tools/px_romfs_pruner.py
-
-# Turn the ROMFS image into an object file
-$(ROMFS_OBJ): $(ROMFS_IMG) $(GLOBAL_DEPS)
-	$(call BIN_TO_OBJ,$<,$@,romfs_img)
-
-# Generate the ROMFS image from the root
-$(ROMFS_IMG): $(ROMFS_SCRATCH) $(ROMFS_DEPS) $(GLOBAL_DEPS)
-	@$(ECHO) "ROMFS:   $@"
-	$(Q) $(GENROMFS) -f $@ -d $(ROMFS_SCRATCH) -V "NSHInitVol"
-
-# Construct the ROMFS scratch root from the canonical root
-$(ROMFS_SCRATCH): $(ROMFS_DEPS) $(GLOBAL_DEPS)
-	$(Q) $(MKDIR) -p $(ROMFS_SCRATCH)
-	$(Q) $(COPYDIR) $(ROMFS_ROOT)/* $(ROMFS_SCRATCH)
-# delete all files in ROMFS_SCRATCH which start with a . or end with a ~
-	$(Q) $(RM) $(ROMFS_SCRATCH)/*/.[!.]* $(ROMFS_SCRATCH)/*/*~
-ifneq ($(ROMFS_EXTRA_FILES),)
-	$(Q) $(MKDIR) -p $(ROMFS_SCRATCH)/extras
-	$(Q) $(COPY) $(ROMFS_EXTRA_FILES) $(ROMFS_SCRATCH)/extras
-endif
-	$(Q) $(PYTHON) -u $(ROMFS_PRUNER) --folder $(ROMFS_SCRATCH)
-
-EXTRA_CLEANS		+= $(ROMGS_OBJ) $(ROMFS_IMG)
-
-endif
-
-################################################################################
-# Builtin command list generation
-################################################################################
-
-#
-# Builtin commands can be generated by the configuration, in which case they
-# must refer to commands that already exist, or indirectly generated by modules
-# when they are built.
-#
-# The configuration supplies builtin command information in the BUILTIN_COMMANDS
-# variable. Applications make empty files in $(WORK_DIR)/builtin_commands whose
-# filename contains the same information.
-#
-# In each case, the command information consists of four fields separated with a
-# period. These fields are the command's name, its thread priority, its stack size
-# and the name of the function to call when starting the thread.
-#
-BUILTIN_CSRC		 = $(WORK_DIR)builtin_commands.c
-
-# command definitions from modules (may be empty at Makefile parsing time...)
-MODULE_COMMANDS		 = $(subst COMMAND.,,$(notdir $(wildcard $(WORK_DIR)builtin_commands/COMMAND.*)))
-
-# We must have at least one pre-defined builtin command in order to generate
-# any of this.
-#
-ifneq ($(BUILTIN_COMMANDS),)
-
-# (BUILTIN_PROTO,<cmdspec>,<outputfile>)
-define BUILTIN_PROTO
-	$(ECHO) 'extern int $(word 4,$1)(int argc, char *argv[]);' >> $2;
-endef
-
-# (BUILTIN_DEF,<cmdspec>,<outputfile>)
-define BUILTIN_DEF
-	$(ECHO) '    {"$(word 1,$1)", $(word 2,$1), $(word 3,$1), $(word 4,$1)},' >> $2;
-endef
-
-# Don't generate until modules have updated their command files
-$(BUILTIN_CSRC):	$(GLOBAL_DEPS) $(MODULE_OBJS) $(MODULE_MKFILES) $(BUILTIN_COMMAND_FILES)
-	@$(ECHO) "CMDS:    $@"
-	$(Q) $(ECHO) '/* builtin command list - automatically generated, do not edit */' > $@
-	$(Q) $(ECHO) '#include <nuttx/config.h>' >> $@
-	$(Q) $(ECHO) '#include <nuttx/binfmt/builtin.h>' >> $@
-	$(Q) $(foreach spec,$(BUILTIN_COMMANDS),$(call BUILTIN_PROTO,$(subst ., ,$(spec)),$@))
-	$(Q) $(foreach spec,$(MODULE_COMMANDS),$(call BUILTIN_PROTO,$(subst ., ,$(spec)),$@))
-	$(Q) $(ECHO) 'const struct builtin_s g_builtins[] = {' >> $@
-	$(Q) $(foreach spec,$(BUILTIN_COMMANDS),$(call BUILTIN_DEF,$(subst ., ,$(spec)),$@))
-	$(Q) $(foreach spec,$(MODULE_COMMANDS),$(call BUILTIN_DEF,$(subst ., ,$(spec)),$@))
-	$(Q) $(ECHO) '    {NULL, 0, 0, NULL}' >> $@
-	$(Q) $(ECHO) '};' >> $@
-	$(Q) $(ECHO) 'const int g_builtin_count = $(words $(BUILTIN_COMMANDS) $(MODULE_COMMANDS));' >> $@
-
-SRCS			+= $(BUILTIN_CSRC)
-
-EXTRA_CLEANS		+= $(BUILTIN_CSRC)
-
-endif
+ifeq ($(PX4_TARGET_OS),nuttx)
+include $(MK_DIR)/nuttx/nuttx_romfs.mk
 endif
 
 ################################################################################
@@ -458,19 +338,6 @@ endif
 # Build rules
 ################################################################################
 
-ifeq ($(PX4_TARGET_OS),nuttx)
-#
-# What we're going to build.
-#
-PRODUCT_BUNDLE		 = $(WORK_DIR)firmware.px4
-PRODUCT_BIN		 = $(WORK_DIR)firmware.bin
-PRODUCT_ELF		 = $(WORK_DIR)firmware.elf
-PRODUCT_PARAMXML = $(WORK_DIR)/parameters.xml
-
-.PHONY:			firmware
-firmware:		$(PRODUCT_BUNDLE)
-endif
-
 #
 # Object files we will generate from sources
 #
@@ -491,68 +358,21 @@ $(filter %.cpp.o,$(OBJS)): $(WORK_DIR)%.cpp.o: %.cpp $(GLOBAL_DEPS)
 $(filter %.S.o,$(OBJS)): $(WORK_DIR)%.S.o: %.S $(GLOBAL_DEPS)
 	$(call ASSEMBLE,$<,$@)
 
-ifeq ($(PX4_TARGET_OS),nuttx)
-#
-# Built product rules
-#
-
-$(PRODUCT_BUNDLE):	$(PRODUCT_BIN)
-	@$(ECHO) %% Generating $@
-ifdef GEN_PARAM_XML
-	$(Q) $(PYTHON) $(PX4_BASE)/Tools/px_process_params.py --src-path $(PX4_BASE)/src --board CONFIG_ARCH_BOARD_$(CONFIG_BOARD) --xml
-	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
-		--git_identity $(PX4_BASE) \
-		--parameter_xml $(PRODUCT_PARAMXML) \
-		--image $< > $@
-else
-	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
-		--git_identity $(PX4_BASE) \
-		--image $< > $@
-endif
-
-$(PRODUCT_BIN):		$(PRODUCT_ELF)
-	$(call SYM_TO_BIN,$<,$@)
-
-$(PRODUCT_ELF):		$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS) $(GLOBAL_DEPS) $(LINK_DEPS) $(MODULE_MKFILES)
-	$(call LINK,$@,$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS))
-
-#
-# Utility rules
-#
-
-.PHONY: upload
-upload:	$(PRODUCT_BUNDLE) $(PRODUCT_BIN)
-	$(Q) $(MAKE) -f $(PX4_MK_DIR)/upload.mk \
-		METHOD=serial \
-		CONFIG=$(CONFIG) \
-		BOARD=$(BOARD) \
-		BUNDLE=$(PRODUCT_BUNDLE) \
-		BIN=$(PRODUCT_BIN)
-
-.PHONY: clean
-clean:			$(MODULE_CLEANS)
-	@$(ECHO) %% cleaning
-	$(Q) $(REMOVE) $(PRODUCT_BUNDLE) $(PRODUCT_BIN) $(PRODUCT_ELF)
-	$(Q) $(REMOVE) $(OBJS) $(DEP_INCLUDES) $(EXTRA_CLEANS)
-	$(Q) $(RMDIR) $(NUTTX_EXPORT_DIR)
-endif
-
 # Include the OS specific build rules
 # The rules must define the "firmware" make target
 #
 
 ifeq ($(PX4_TARGET_OS),nuttx)
-# TODO
-# Move above nuttx specific rules to $(MK_DIR)/nuttx_romfs.mk
+include $(MK_DIR)/nuttx/nuttx_px4.mk
 endif
 ifeq ($(PX4_TARGET_OS),posix)
-include $(MK_DIR)/posix_elf.mk
+include $(MK_DIR)/posix/posix_elf.mk
 endif
 ifeq ($(PX4_TARGET_OS),posix-arm)
-include $(MK_DIR)/posix_elf.mk
+include $(MK_DIR)/posix/posix_elf.mk
 endif
 ifeq ($(PX4_TARGET_OS),qurt)
-include $(MK_DIR)/qurt_elf.mk
+include $(MK_DIR)/qurt/qurt_elf.mk
 endif
 
 #
diff --git a/makefiles/firmware_nuttx.mk b/makefiles/nuttx/firmware_nuttx.mk
similarity index 71%
rename from makefiles/firmware_nuttx.mk
rename to makefiles/nuttx/firmware_nuttx.mk
index 77bb2bace0..644c3a0e72 100644
--- a/makefiles/firmware_nuttx.mk
+++ b/makefiles/nuttx/firmware_nuttx.mk
@@ -1,38 +1,6 @@
-#
-#   Copyright (c) 2012-2015 PX4 Development Team. All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions
-# are met:
-#
-# 1. Redistributions of source code must retain the above copyright
-#    notice, this list of conditions and the following disclaimer.
-# 2. Redistributions in binary form must reproduce the above copyright
-#    notice, this list of conditions and the following disclaimer in
-#    the documentation and/or other materials provided with the
-#    distribution.
-# 3. Neither the name PX4 nor the names of its contributors may be
-#    used to endorse or promote products derived from this software
-#    without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
-# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
-# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
-# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
-# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
-# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
-# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-# POSSIBILITY OF SUCH DAMAGE.
-#
-
 #
 # Built products
 #
-
 DESIRED_FIRMWARES 	 = $(foreach config,$(CONFIGS),$(IMAGE_DIR)$(config).px4)
 STAGED_FIRMWARES	 = $(foreach config,$(KNOWN_CONFIGS),$(IMAGE_DIR)$(config).px4)
 FIRMWARES		 = $(foreach config,$(KNOWN_CONFIGS),$(BUILD_DIR)$(config).build/firmware.px4)
@@ -57,7 +25,7 @@ $(STAGED_FIRMWARES): $(IMAGE_DIR)%.px4: $(BUILD_DIR)%.build/firmware.px4
 .PHONY: $(FIRMWARES)
 $(BUILD_DIR)%.build/firmware.px4: config   = $(patsubst $(BUILD_DIR)%.build/firmware.px4,%,$@)
 $(BUILD_DIR)%.build/firmware.px4: work_dir = $(BUILD_DIR)$(config).build/
-$(FIRMWARES): $(BUILD_DIR)%.build/firmware.px4:	generateuorbtopicheaders checksubmodules
+$(FIRMWARES): $(BUILD_DIR)%.build/firmware.px4:	checkgitversion generateuorbtopicheaders checksubmodules
 	@$(ECHO) %%%%
 	@$(ECHO) %%%% Building $(config) in $(work_dir)
 	@$(ECHO) %%%%
@@ -134,6 +102,7 @@ menuconfig: $(NUTTX_SRC)
 	$(Q) (cd $(NUTTX_SRC)/configs && $(COPYDIR) $(PX4_BASE)nuttx-configs/$(BOARD) .)
 	$(Q) (cd $(NUTTX_SRC)tools && ./configure.sh $(BOARD)/nsh)
 	@$(ECHO) %% Running menuconfig for $(BOARD)
+	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) oldconfig
 	$(Q) $(MAKE) -r -j$(J) -C $(NUTTX_SRC) -r $(MQUIET) menuconfig
 	@$(ECHO) %% Saving configuration file
 	$(Q)$(COPY) $(NUTTX_SRC).config $(PX4_BASE)nuttx-configs/$(BOARD)/nsh/defconfig
@@ -142,9 +111,10 @@ menuconfig:
 	@$(ECHO) ""
 	@$(ECHO) "The menuconfig goal must be invoked without any other goal being specified"
 	@$(ECHO) ""
+
 endif
 
-$(NUTTX_SRC): checksubmodules
+$(NUTTX_SRC): checkgitversion checksubmodules
 
 $(UAVCAN_DIR):
 	$(Q) (./Tools/check_submodules.sh)
diff --git a/makefiles/nuttx.mk b/makefiles/nuttx/nuttx.mk
similarity index 100%
rename from makefiles/nuttx.mk
rename to makefiles/nuttx/nuttx.mk
diff --git a/makefiles/nuttx/nuttx_px4.mk b/makefiles/nuttx/nuttx_px4.mk
new file mode 100644
index 0000000000..861eff957f
--- /dev/null
+++ b/makefiles/nuttx/nuttx_px4.mk
@@ -0,0 +1,86 @@
+#
+#   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+#
+# What we're going to build.
+#
+PRODUCT_BUNDLE		 = $(WORK_DIR)firmware.px4
+PRODUCT_BIN		 = $(WORK_DIR)firmware.bin
+PRODUCT_ELF		 = $(WORK_DIR)firmware.elf
+PRODUCT_PARAMXML = $(WORK_DIR)/parameters.xml
+
+.PHONY:			firmware
+firmware:		$(PRODUCT_BUNDLE)
+
+#
+# Built product rules
+#
+
+$(PRODUCT_BUNDLE):	$(PRODUCT_BIN)
+	@$(ECHO) %% Generating $@
+ifdef GEN_PARAM_XML
+	$(Q) $(PYTHON) $(PX4_BASE)/Tools/px_process_params.py --src-path $(PX4_BASE)/src --board CONFIG_ARCH_BOARD_$(CONFIG_BOARD) --xml
+	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
+		--git_identity $(PX4_BASE) \
+		--parameter_xml $(PRODUCT_PARAMXML) \
+		--image $< > $@
+else
+	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
+		--git_identity $(PX4_BASE) \
+		--image $< > $@
+endif
+
+$(PRODUCT_BIN):		$(PRODUCT_ELF)
+	$(call SYM_TO_BIN,$<,$@)
+
+$(PRODUCT_ELF):		$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS) $(GLOBAL_DEPS) $(LINK_DEPS) $(MODULE_MKFILES)
+	$(call LINK,$@,$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS))
+
+#
+# Utility rules
+#
+
+.PHONY: upload
+upload:	$(PRODUCT_BUNDLE) $(PRODUCT_BIN)
+	$(Q) $(MAKE) -f $(PX4_MK_DIR)/nuttx/upload.mk \
+		METHOD=serial \
+		CONFIG=$(CONFIG) \
+		BOARD=$(BOARD) \
+		BUNDLE=$(PRODUCT_BUNDLE) \
+		BIN=$(PRODUCT_BIN)
+
+.PHONY: clean
+clean:			$(MODULE_CLEANS)
+	@$(ECHO) %% cleaning
+	$(Q) $(REMOVE) $(PRODUCT_BUNDLE) $(PRODUCT_BIN) $(PRODUCT_ELF)
+	$(Q) $(REMOVE) $(OBJS) $(DEP_INCLUDES) $(EXTRA_CLEANS)
+	$(Q) $(RMDIR) $(NUTTX_EXPORT_DIR)
+
diff --git a/makefiles/nuttx_romfs.mk b/makefiles/nuttx/nuttx_romfs.mk
similarity index 79%
rename from makefiles/nuttx_romfs.mk
rename to makefiles/nuttx/nuttx_romfs.mk
index 42aeb3b8d4..611ac18842 100644
--- a/makefiles/nuttx_romfs.mk
+++ b/makefiles/nuttx/nuttx_romfs.mk
@@ -29,10 +29,6 @@
 # POSSIBILITY OF SUCH DAMAGE.
 #
 
-#
-# Makefile for PX4 Nuttx based firmware images.
-#
-
 ################################################################################
 # ROMFS generation
 ################################################################################
@@ -158,62 +154,3 @@ EXTRA_CLEANS		+= $(BUILTIN_CSRC)
 
 endif
 
-################################################################################
-# Build rules
-################################################################################
-
-#
-# What we're going to build.
-#
-PRODUCT_BUNDLE		 = $(WORK_DIR)firmware.px4
-PRODUCT_BIN		 = $(WORK_DIR)firmware.bin
-PRODUCT_ELF		 = $(WORK_DIR)firmware.elf
-PRODUCT_PARAMXML = $(WORK_DIR)/parameters.xml
-
-.PHONY:			firmware
-firmware:		$(PRODUCT_BUNDLE)
-
-#
-# Built product rules
-#
-
-$(PRODUCT_BUNDLE):	$(PRODUCT_BIN)
-	@$(ECHO) %% Generating $@
-ifdef GEN_PARAM_XML
-	python $(PX4_BASE)/Tools/px_process_params.py --src-path $(PX4_BASE)/src --board CONFIG_ARCH_BOARD_$(CONFIG_BOARD) --xml
-	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
-		--git_identity $(PX4_BASE) \
-		--parameter_xml $(PRODUCT_PARAMXML) \
-		--image $< > $@
-else
-	$(Q) $(MKFW) --prototype $(IMAGE_DIR)/$(BOARD).prototype \
-		--git_identity $(PX4_BASE) \
-		--image $< > $@
-endif
-
-$(PRODUCT_BIN):		$(PRODUCT_ELF)
-	$(call SYM_TO_BIN,$<,$@)
-
-$(PRODUCT_ELF):		$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS) $(GLOBAL_DEPS) $(LINK_DEPS) $(MODULE_MKFILES)
-	$(call LINK,$@,$(OBJS) $(MODULE_OBJS) $(LIBRARY_LIBS))
-
-#
-# Utility rules
-#
-
-.PHONY: upload
-upload:	$(PRODUCT_BUNDLE) $(PRODUCT_BIN)
-	$(Q) $(MAKE) -f $(PX4_MK_DIR)/upload.mk \
-		METHOD=serial \
-		CONFIG=$(CONFIG) \
-		BOARD=$(BOARD) \
-		BUNDLE=$(PRODUCT_BUNDLE) \
-		BIN=$(PRODUCT_BIN)
-
-.PHONY: clean
-clean:			$(MODULE_CLEANS)
-	@$(ECHO) %% cleaning
-	$(Q) $(REMOVE) $(PRODUCT_BUNDLE) $(PRODUCT_BIN) $(PRODUCT_ELF)
-	$(Q) $(REMOVE) $(OBJS) $(DEP_INCLUDES) $(EXTRA_CLEANS)
-	$(Q) $(RMDIR) $(NUTTX_EXPORT_DIR)
-
diff --git a/makefiles/upload.mk b/makefiles/nuttx/upload.mk
similarity index 100%
rename from makefiles/upload.mk
rename to makefiles/nuttx/upload.mk
diff --git a/makefiles/posix-arm.mk b/makefiles/posix-arm/posix-arm.mk
similarity index 100%
rename from makefiles/posix-arm.mk
rename to makefiles/posix-arm/posix-arm.mk
diff --git a/makefiles/firmware_posix.mk b/makefiles/posix/firmware_posix.mk
similarity index 100%
rename from makefiles/firmware_posix.mk
rename to makefiles/posix/firmware_posix.mk
diff --git a/makefiles/posix.mk b/makefiles/posix/posix.mk
similarity index 100%
rename from makefiles/posix.mk
rename to makefiles/posix/posix.mk
diff --git a/makefiles/posix_elf.mk b/makefiles/posix/posix_elf.mk
similarity index 100%
rename from makefiles/posix_elf.mk
rename to makefiles/posix/posix_elf.mk
diff --git a/makefiles/firmware_qurt.mk b/makefiles/qurt/firmware_qurt.mk
similarity index 100%
rename from makefiles/firmware_qurt.mk
rename to makefiles/qurt/firmware_qurt.mk
diff --git a/makefiles/qurt.mk b/makefiles/qurt/qurt.mk
similarity index 100%
rename from makefiles/qurt.mk
rename to makefiles/qurt/qurt.mk
diff --git a/makefiles/qurt_elf.mk b/makefiles/qurt/qurt_elf.mk
similarity index 100%
rename from makefiles/qurt_elf.mk
rename to makefiles/qurt/qurt_elf.mk
diff --git a/makefiles/qurt/toolchain_hexagon.mk b/makefiles/qurt/toolchain_hexagon.mk
index 8f44a84946..8b5bf5423e 100644
--- a/makefiles/qurt/toolchain_hexagon.mk
+++ b/makefiles/qurt/toolchain_hexagon.mk
@@ -209,7 +209,7 @@ AFLAGS			 = $(CFLAGS) -D__ASSEMBLY__ \
 			   $(EXTRADEFINES) \
 			   $(EXTRAAFLAGS)
 
-LDSCRIPT		 = $(PX4_BASE)/posix-configs/posixtest/scripts/ld.script
+LDSCRIPT		 = $(PX4_BASE)/makefiles/posix/ld.script
 # Flags we pass to the linker
 #
 LDFLAGS			+=  -g -mv5 -nostdlib -mG0lib -G0 -fpic -shared \
diff --git a/posix-configs/SITL/README.md b/posix-configs/SITL/README.md
index 8a036eea90..1bd38c0603 100644
--- a/posix-configs/SITL/README.md
+++ b/posix-configs/SITL/README.md
@@ -18,6 +18,13 @@ Steps
 
 1. Connect the RC Controller (PIXHAWK) to the PX4 machine using USB.  Verify the `/dev/ttyACM0` device appears.  Make sure that the persmissions of this device allow the PX4 app to open the device for read/write (`sudo chmod 777 /dev/ttyACM0`).
 
+1. Create the following diretories in "`./Firmware/Build/posix_sitl.build/`":
+```
+> cd ./Firmware/Build/posix_sitl.build
+> mkdir -p rootfs/fs/microsd
+> mkdir -p rootfs/eeprom
+```
+
 1. Launch PX4 from the SITL build directory "`./Firmware/Build/posix_sitl.build/`" using the command below.  The optional `<startup_file>` can be used to cause a set of commands to be entered into the PX4 shell at startup.  
 ```
 > ./mainapp <startup_file> 
diff --git a/posix-configs/SITL/init/rcS b/posix-configs/SITL/init/rcS
index cc4c76526f..8a6203a0bc 100644
--- a/posix-configs/SITL/init/rcS
+++ b/posix-configs/SITL/init/rcS
@@ -26,7 +26,7 @@ param set RC1_MAX 2015
 param set RC1_MIN 996
 param set RC1_TRIM 1502
 param set RC1_REV -1
-param set RC2_MAX 2016 
+param set RC2_MAX 2016
 param set RC2_MIN 995
 param set RC2_TRIM 1500
 param set RC3_MAX 2003