diff --git a/CMakeLists.txt b/CMakeLists.txt
index bcf3e3741f..b19216a6cf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -364,7 +364,9 @@ px4_generate_messages(TARGET msg_gen
 	OS ${OS}
 	DEPENDS git_genmsg git_gencpp prebuild_targets
 	)
-px4_generate_parameters_xml(OUT parameters.xml BOARD ${BOARD})
+px4_generate_parameters_xml(OUT parameters.xml 
+                            BOARD ${BOARD}
+                            SCOPE ${PX4_SOURCE_DIR}/cmake/configs/${OS}_${BOARD}_${LABEL}.cmake)
 px4_generate_airframes_xml(OUT airframes.xml BOARD ${BOARD})
 add_custom_target(xml_gen
 	DEPENDS parameters.xml airframes.xml)
diff --git a/Tools/px4params/__init__.py b/Tools/px4params/__init__.py
index 3a9f1e2c6d..653b53bbf1 100644
--- a/Tools/px4params/__init__.py
+++ b/Tools/px4params/__init__.py
@@ -1 +1 @@
-__all__ = ["srcscanner", "srcparser", "xmlout", "dokuwikiout", "dokuwikirpc"]
\ No newline at end of file
+__all__ = ["srcscanner", "srcparser", "xmlout", "dokuwikiout", "dokuwikirpc", "cmakeparser", "scope"]
diff --git a/Tools/px4params/cmakeparser.py b/Tools/px4params/cmakeparser.py
new file mode 100644
index 0000000000..80ce9e2923
--- /dev/null
+++ b/Tools/px4params/cmakeparser.py
@@ -0,0 +1,37 @@
+import re
+import codecs
+import sys
+
+class CMakeParser(object):
+    """
+    Parses provided data and stores all found paths in scope.
+    """
+    re_split_lines = re.compile(r'[\r\n]+')
+    re_comment = re.compile(r'^\#')
+    re_start = re.compile(r'set\s*\(\s*config_module_list')
+    re_end = re.compile(r'\)\s*')
+
+    def Parse(self, scope, contents):
+        """
+        Incrementally parse cmake file contents and append all found path scope
+        to scope.
+        """
+        # This code is essentially a comment-parsing grammar. "state"
+        # represents parser state. It contains human-readable state
+        # names.
+        state = None
+        for line in self.re_split_lines.split(contents):
+            line = line.strip()
+            # Ignore empty lines
+            if line == "":
+                continue
+            if self.re_comment.match(line):
+                continue
+            elif self.re_start.match(line):
+                state = "gather"
+                continue
+            elif state is not None and state == "gather":
+                if self.re_end.match(line):
+                    return True
+                scope.Add(line)
+        return False
diff --git a/Tools/px4params/scope.py b/Tools/px4params/scope.py
new file mode 100644
index 0000000000..212b591513
--- /dev/null
+++ b/Tools/px4params/scope.py
@@ -0,0 +1,32 @@
+import os
+import re
+
+class Scope(object):
+    """
+    Single parameter group
+    """
+    re_deep_lines = re.compile(r'.*\/.*\/')
+    def __init__(self,):
+        self.scope = set()
+
+
+    def __str__(self):
+        return self.scope.__str__()
+
+    def Add(self, scope):
+        """
+        Add Scope to set
+        """
+        self.scope.add(scope)
+
+    def Has(self, scope):
+        """
+        Check for existance
+        """
+        if len(self.scope) == 0:
+            return True
+        # Anything in the form xxxxx/yyyyy/zzzzz....
+        # is treated as xxxxx/yyyyy
+        while (self.re_deep_lines.match(scope)):
+            scope = os.path.dirname(scope)
+        return scope in self.scope
diff --git a/Tools/px4params/srcscanner.py b/Tools/px4params/srcscanner.py
index 085c956139..aef0ddeffc 100644
--- a/Tools/px4params/srcscanner.py
+++ b/Tools/px4params/srcscanner.py
@@ -1,6 +1,7 @@
 import os
 import re
 import codecs
+import sys
 
 class SourceScanner(object):
     """
@@ -8,24 +9,25 @@ class SourceScanner(object):
     to the Parser.
     """
 
-    def ScanDir(self, srcdir, parser):
+    def ScanDir(self, srcdirs, parser):
         """
         Scans provided path and passes all found contents to the parser using
         parser.Parse method.
         """
         extensions1 = tuple([".h"])
         extensions2 = tuple([".cpp", ".c"])
-        for dirname, dirnames, filenames in os.walk(srcdir):
-            for filename in filenames:
-                if filename.endswith(extensions1):
-                    path = os.path.join(dirname, filename)
-                    if not self.ScanFile(path, parser):
-                        return False
-            for filename in filenames:
-                if filename.endswith(extensions2):
-                    path = os.path.join(dirname, filename)
-                    if not self.ScanFile(path, parser):
-                        return False
+        for srcdir in srcdirs:
+            for dirname, dirnames, filenames in os.walk(srcdir):
+                for filename in filenames:
+                    if filename.endswith(extensions1):
+                        path = os.path.join(dirname, filename)
+                        if not self.ScanFile(path, parser):
+                            return False
+                for filename in filenames:
+                    if filename.endswith(extensions2):
+                        path = os.path.join(dirname, filename)
+                        if not self.ScanFile(path, parser):
+                            return False
         return True
 
     def ScanFile(self, path, parser):
diff --git a/Tools/px_generate_params.py b/Tools/px_generate_params.py
index aef00aec1a..a626716919 100755
--- a/Tools/px_generate_params.py
+++ b/Tools/px_generate_params.py
@@ -3,87 +3,23 @@ import xml.etree.ElementTree as ET
 import os
 import re
 import codecs
+import sys
 
-class Scope(object):
-	"""
-	Single parameter group
-	"""
-	re_deep_lines = re.compile(r'.*\/.*\/')
-	def __init__(self, ):
-		self.scope = set()
-
-
-	def __str__(self):
-		return self.scope.__str__()
-
-	def Add(self, scope):
-		"""
-		Add Scope to set
-		"""
-		self.scope.add(scope)
-
-	def Has(self, scope):
-		"""
-		Check for existance
-		"""
-		if len(self.scope) == 0:
-			return True
-		# Anything in the form xxxxx/yyyyy/zzzzz....
-		# is treated as xxxxx/yyyyy
-		while (self.re_deep_lines.match(scope)):
-			scope = os.path.dirname(scope)
-		return scope in self.scope
-
-
-class CMakeParser(object):
-	"""
-	Parses provided data and stores all found paths in scope.
-	"""
-	re_split_lines = re.compile(r'[\r\n]+')
-	re_comment = re.compile(r'^\#')
-	re_start = re.compile(r'set\s*\(\s*config_module_list')
-	re_end = re.compile(r'\)\s*')
-
-	def Parse(self, scope, contents):
-		"""
-		Incrementally parse cmake file contents and append all found path scope
-		to scope.
-		"""
-		# This code is essentially a comment-parsing grammar. "state"
-		# represents parser state. It contains human-readable state
-		# names.
-		state = None
-		for line in self.re_split_lines.split(contents):
-			line = line.strip()
-			# Ignore empty lines
-			if line == "":
-				continue
-			if self.re_comment.match(line):
-				continue
-			elif self.re_start.match(line):
-				state = "gather"
-				continue
-			elif state is not None and state == "gather":
-				if self.re_end.match(line):
-					return True
-				scope.Add(line)
-		return False
-
+from px4params import scope, cmakeparser
 
 if len(os.sys.argv) < 2:
-	print("Error in %s" % os.sys.argv[0])
-	print("Usage: %s <parameters.xml> [cmake-file-scoping] " % os.sys.argv[0])
-	raise SystemExit
+    print("Error in %s" % os.sys.argv[0])
+    print("Usage: %s <parameters.xml> [cmake-file-scoping] " % os.sys.argv[0])
+    raise SystemExit
 
-
-scope = Scope()
+cmake_scope = scope.Scope()
 if len(os.sys.argv) == 3:
 	with codecs.open(os.sys.argv[2], 'r', 'utf-8') as f:
 		try:
 			contents = f.read()
 			f.close()
-			parser  = CMakeParser()
-			parser.Parse(scope, contents)
+			parser = cmakeparser.CMakeParser()
+			parser.Parse(cmake_scope, contents)
 		except:
 			contents = ''
 			print('Failed reading file: %s, skipping scoping.' % os.sys.argv[2])
@@ -110,7 +46,9 @@ struct px4_parameters_t {
 start_name = ""
 end_name = ""
 
+sys.stderr.write("cmake_scope: " + str(cmake_scope) + "\n")
 for group in root:
+	sys.stderr.write(str(group.attrib) + group.tag + "\n")
 	if group.tag == "group" and "no_code_generation" not in group.attrib:
 		section = """
 	/*****************************************************************
@@ -118,7 +56,7 @@ for group in root:
 	 ****************************************************************/""" % group.attrib["name"]
 		for param in group:
 			scope_ = param.find('scope').text
-			if not scope.Has(scope_):
+			if not cmake_scope.Has(scope_):
 				continue
 			if not start_name:
 				start_name = param.attrib["name"]
@@ -156,7 +94,7 @@ for group in root:
 	 ****************************************************************/""" % group.attrib["name"]
 		for param in group:
 			scope_ = param.find('scope').text
-			if not scope.Has(scope_):
+			if not cmake_scope.Has(scope_):
 				continue
 			if not start_name:
 				start_name = param.attrib["name"]
diff --git a/Tools/px_process_params.py b/Tools/px_process_params.py
index 7bac8834d3..38a1eec52b 100644
--- a/Tools/px_process_params.py
+++ b/Tools/px_process_params.py
@@ -50,7 +50,10 @@ from __future__ import print_function
 import sys
 import os
 import argparse
-from px4params import srcscanner, srcparser, xmlout, dokuwikiout, dokuwikirpc
+from px4params import srcscanner, srcparser, xmlout, dokuwikiout, dokuwikirpc, scope, cmakeparser
+
+import re
+import codecs
 
 def main():
     # Parse command line arguments
@@ -108,6 +111,8 @@ def main():
                         default="Automagically updated parameter documentation from code.",
                         help="DokuWiki page edit summary")
     parser.add_argument('-v', '--verbose', action='store_true', help="verbose output")
+    parser.add_argument('--scope', default=None, action='store', help="pass the scope (list of compiled modules)")
+
     args = parser.parse_args()
 
     # Check for valid command
@@ -122,8 +127,28 @@ def main():
 
     # Scan directories, and parse the files
     if (args.verbose): print("Scanning source path " + args.src_path)
-    if not scanner.ScanDir(args.src_path, parser):
-        sys.exit(1)
+    
+    use_scope = False
+    cmake_scope = scope.Scope();
+    
+    if args.scope:
+        with codecs.open(args.scope, 'r', 'utf-8') as f:
+            try:
+                contents = f.read()
+                f.close()
+                cmake_parser = cmakeparser.CMakeParser()
+                cmake_parser.Parse(cmake_scope, contents)
+                use_scope = True
+            except:
+                use_scope = False
+                pass
+    if use_scope:
+        print(cmake_scope.scope)
+        if not scanner.ScanDir([os.path.join(args.src_path, p) for p in cmake_scope.scope], parser):
+            sys.exit(1)
+    else:    
+        if not scanner.ScanDir([args.src_path], parser):
+            sys.exit(1)
     if not parser.Validate():
         sys.exit(1)
     param_groups = parser.GetParamGroups()
diff --git a/cmake/common/px4_base.cmake b/cmake/common/px4_base.cmake
index 6223df4aa5..b0243f99ba 100644
--- a/cmake/common/px4_base.cmake
+++ b/cmake/common/px4_base.cmake
@@ -1014,7 +1014,7 @@ endfunction()
 function(px4_generate_parameters_xml)
 	px4_parse_function_args(
 		NAME px4_generate_parameters_xml
-		ONE_VALUE OUT BOARD
+		ONE_VALUE OUT BOARD SCOPE
 		REQUIRED OUT BOARD
 		ARGN ${ARGN})
 	set(path ${PX4_SOURCE_DIR}/src)
@@ -1023,7 +1023,7 @@ function(px4_generate_parameters_xml)
 		)
 	add_custom_command(OUTPUT ${OUT}
 		COMMAND ${PYTHON_EXECUTABLE} ${PX4_SOURCE_DIR}/Tools/px_process_params.py
-			-s ${path} --board CONFIG_ARCH_${BOARD} --xml --inject-xml
+			-s ${path} --board CONFIG_ARCH_${BOARD} --xml --inject-xml --scope ${SCOPE}
 		DEPENDS ${param_src_files}
 		)
 	set(${OUT} ${${OUT}} PARENT_SCOPE)
diff --git a/cmake/nuttx/px4_impl_nuttx.cmake b/cmake/nuttx/px4_impl_nuttx.cmake
index 8edaf25dea..627f098ae6 100644
--- a/cmake/nuttx/px4_impl_nuttx.cmake
+++ b/cmake/nuttx/px4_impl_nuttx.cmake
@@ -435,7 +435,7 @@ function(px4_nuttx_add_romfs)
 			--obj romfs.o
 			--var romfs_img
 			--bin romfs.bin
-		DEPENDS ${romfs_src_files} ${extras}
+		DEPENDS ${romfs_src_files} ${extras} ${optional_files}
 		WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
 		)
 	add_library(${OUT} STATIC romfs.o)