diff --git a/bsp/lpc43xx/M0/SConstruct b/bsp/lpc43xx/M0/SConstruct
index 62cebd454f00f5daaa13f1067da47aa6dc361b52..c7967d02f6fe07393fe306df24b7649fee150de9 100644
--- a/bsp/lpc43xx/M0/SConstruct
+++ b/bsp/lpc43xx/M0/SConstruct
@@ -25,5 +25,23 @@ Export('rtconfig')
 # prepare building environment
 objs = PrepareBuilding(env, RTT_ROOT, has_libcpu=False)
 
+if rtconfig.CROSS_TOOL == 'gcc':
+    import glob
+    # Remove the .o for M0 left on the drivers dir.
+    for i in glob.glob(GetCurrentDir() + '/../drivers/*.o'):
+        print 'RM %s' % i
+        os.unlink(i)
+
+    if sys.platform.startswith('linux'):
+        import glob
+        ocwd = os.getcwdu()
+        res = os.system('cd ../Libraries/; find -name \*.o -exec rm {} \;')
+        os.chdir(ocwd)
+    else:
+        # Assume Windows.
+        ocwd = os.getcwdu()
+        print 'TODO: remove the object files in ../Libraries'
+        os.chdir(ocwd)
+
 # do building 
 DoBuilding(TARGET, objs)
diff --git a/bsp/lpc43xx/M4/SConstruct b/bsp/lpc43xx/M4/SConstruct
index 17f5eaf11c8c7b79a483222df5f9a149e0fef0c8..7b02b732d48f27beb23e9e4da155ea95f9f35828 100644
--- a/bsp/lpc43xx/M4/SConstruct
+++ b/bsp/lpc43xx/M4/SConstruct
@@ -28,6 +28,7 @@ objs = PrepareBuilding(env, RTT_ROOT, has_libcpu=False)
 if rtconfig.CROSS_TOOL == 'gcc':
     print 'build M0 code first'
     if sys.platform.startswith('linux'):
+        import glob
         ocwd = os.getcwdu()
         os.chdir('../M0')
         res = os.system('scons')
@@ -35,12 +36,19 @@ if rtconfig.CROSS_TOOL == 'gcc':
             print 'build M0 exit with code %d\n' % res
             sys.exit(res)
         os.chdir(ocwd)
+        res = os.system('cd ../Libraries/; find -name \*.o -exec rm {} \;')
+        os.chdir(ocwd)
     else:
-        # assume Windows.
+        # Assume Windows.
         ocwd = os.getcwdu()
         os.chdir('..\M0')
         os.system('scons.bat')
         os.chdir(ocwd)
 
+    # Remove the .o for M0 left on the drivers dir.
+    for i in glob.glob(GetCurrentDir() + '/../drivers/*.o'):
+        print 'RM %s' % i
+        os.unlink(i)
+
 # do building 
 DoBuilding(TARGET, objs)