diff --git a/HISTORY.rst b/HISTORY.rst
index 1bc72b89..f156f03b 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -7,6 +7,8 @@ PlatformIO 2.0
 2.10.4 (2016-06-??)
 ~~~~~~~~~~~~~~~~~~~
 
+* Better removing unnecessary flags using ``build_unflags`` option
+  (`issue #698 <https://github.com/platformio/platformio/issues/698>`_)
 * Fixed issue with ``platformio init --ide`` command for Python 2.6
 
 2.10.3 (2016-06-15)
diff --git a/platformio/__init__.py b/platformio/__init__.py
index 8746c80d..b2567541 100644
--- a/platformio/__init__.py
+++ b/platformio/__init__.py
@@ -14,7 +14,7 @@
 
 import sys
 
-VERSION = (2, 10, "4.dev0")
+VERSION = (2, 10, "4.dev1")
 __version__ = ".".join([str(s) for s in VERSION])
 
 __title__ = "platformio"
diff --git a/platformio/builder/scripts/basearm.py b/platformio/builder/scripts/basearm.py
index 20892b18..a8dc9cc7 100644
--- a/platformio/builder/scripts/basearm.py
+++ b/platformio/builder/scripts/basearm.py
@@ -40,8 +40,7 @@ env.Replace(
         "-fdata-sections",
         "-Wall",
         "-mthumb",
-        "-mcpu=${BOARD_OPTIONS['build']['cpu']}",
-        "-nostdlib"
+        "-mcpu=${BOARD_OPTIONS['build']['cpu']}"
     ],
 
     CXXFLAGS=[
@@ -57,7 +56,9 @@ env.Replace(
         "-Os",
         "-Wl,--gc-sections,--relax",
         "-mthumb",
-        "-mcpu=${BOARD_OPTIONS['build']['cpu']}"
+        "-mcpu=${BOARD_OPTIONS['build']['cpu']}",
+        "-nostdlib",
+        "-nostartfiles"
     ],
 
     LIBS=["c", "gcc", "m"],
diff --git a/platformio/builder/scripts/espressif.py b/platformio/builder/scripts/espressif.py
index 7c167489..34058955 100644
--- a/platformio/builder/scripts/espressif.py
+++ b/platformio/builder/scripts/espressif.py
@@ -71,8 +71,7 @@ env.Replace(
         "-Wpointer-arith",
         "-Wno-implicit-function-declaration",
         "-Wl,-EL",
-        "-fno-inline-functions",
-        "-nostdlib"
+        "-fno-inline-functions"
     ],
 
     CCFLAGS=[
@@ -82,8 +81,7 @@ env.Replace(
         "-falign-functions=4",
         "-U__STRICT_ANSI__",
         "-ffunction-sections",
-        "-fdata-sections",
-        "-MMD"  # output dependancy info
+        "-fdata-sections"
     ],
 
     CXXFLAGS=[
diff --git a/platformio/builder/scripts/frameworks/mbed.py b/platformio/builder/scripts/frameworks/mbed.py
index 08a9e873..3c7dc2e0 100644
--- a/platformio/builder/scripts/frameworks/mbed.py
+++ b/platformio/builder/scripts/frameworks/mbed.py
@@ -264,13 +264,12 @@ env.Replace(
 )
 
 # restore external build flags
-env.ProcessFlags([
-    env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags")
-])
+env.ProcessFlags(
+    env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags"))
 # remove base flags
 env.ProcessUnFlags(env.get("BUILD_UNFLAGS"))
 # apply user flags
-env.ProcessFlags([env.get("BUILD_FLAGS")])
+env.ProcessFlags(env.get("BUILD_FLAGS"))
 
 # Hook for K64F and K22F
 if board_type in ("frdm_k22f", "frdm_k64f"):
diff --git a/platformio/builder/scripts/ststm32.py b/platformio/builder/scripts/ststm32.py
index 8dbd70ef..3077f74d 100644
--- a/platformio/builder/scripts/ststm32.py
+++ b/platformio/builder/scripts/ststm32.py
@@ -66,11 +66,6 @@ env.Append(
     ],
 
     LIBS=["stdc++", "nosys"],
-
-    LINKFLAGS=[
-        "-nostartfiles",
-        "-nostdlib"
-    ]
 )
 
 #
diff --git a/platformio/builder/scripts/titiva.py b/platformio/builder/scripts/titiva.py
index e705cd62..411eb0cb 100644
--- a/platformio/builder/scripts/titiva.py
+++ b/platformio/builder/scripts/titiva.py
@@ -31,13 +31,6 @@ env.Replace(
     UPLOADCMD='"$UPLOADER" $SOURCES'
 )
 
-env.Append(
-    LINKFLAGS=[
-        "-nostartfiles",
-        "-nostdlib"
-    ]
-)
-
 #
 # Target: Build executable and linkable firmware
 #
diff --git a/platformio/builder/tools/platformio.py b/platformio/builder/tools/platformio.py
index 01b50f57..41341b96 100644
--- a/platformio/builder/tools/platformio.py
+++ b/platformio/builder/tools/platformio.py
@@ -53,13 +53,12 @@ def BuildProgram(env):
         )
 
     # process extra flags from board
-    env.ProcessFlags([
-        env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags")
-    ])
+    env.ProcessFlags(
+        env.get("BOARD_OPTIONS", {}).get("build", {}).get("extra_flags"))
     # remove base flags
     env.ProcessUnFlags(env.get("BUILD_UNFLAGS"))
     # apply user flags
-    env.ProcessFlags([env.get("BUILD_FLAGS")])
+    env.ProcessFlags(env.get("BUILD_FLAGS"))
 
     if env.get("FRAMEWORK"):
         env.BuildFrameworks([
@@ -88,7 +87,7 @@ def BuildProgram(env):
         )
 
     # Handle SRC_BUILD_FLAGS
-    env.ProcessFlags([env.get("SRC_BUILD_FLAGS", None)])
+    env.ProcessFlags(env.get("SRC_BUILD_FLAGS"))
 
     env.Append(
         CPPPATH=["$PROJECTSRC_DIR"],
@@ -117,18 +116,17 @@ def BuildProgram(env):
 
 
 def ProcessFlags(env, flags):
-    for f in flags:
-        if not f:
+    if not flags:
+        return
+    parsed_flags = env.ParseFlags(str(flags))
+    for flag in parsed_flags.pop("CPPDEFINES"):
+        if not isinstance(flag, list):
+            env.Append(CPPDEFINES=flag)
             continue
-        parsed_flags = env.ParseFlags(str(f))
-        for flag in parsed_flags.pop("CPPDEFINES"):
-            if not isinstance(flag, list):
-                env.Append(CPPDEFINES=flag)
-                continue
-            if '\"' in flag[1]:
-                flag[1] = flag[1].replace('\"', '\\\"')
-            env.Append(CPPDEFINES=[flag])
-        env.Append(**parsed_flags)
+        if '\"' in flag[1]:
+            flag[1] = flag[1].replace('\"', '\\\"')
+        env.Append(CPPDEFINES=[flag])
+    env.Append(**parsed_flags)
 
     # fix relative CPPPATH & LIBPATH
     for k in ("CPPPATH", "LIBPATH"):
@@ -153,10 +151,17 @@ def ProcessFlags(env, flags):
 def ProcessUnFlags(env, flags):
     if not flags:
         return
-    for var, values in env.ParseFlags(flags).items():
-        for v in values:
-            if v in env[var]:
-                env[var].remove(v)
+    parsed_flags = env.ParseFlags(flags)
+    all_flags = []
+    for items in parsed_flags.values():
+        all_flags.extend(items)
+    all_flags = set(all_flags)
+
+    for key in parsed_flags.keys():
+        cur_flags = set(env.get(key, []))
+        common = cur_flags & all_flags
+        for item in common:
+            env[key].remove(item)
 
 
 def IsFileWithExt(env, file_, ext):  # pylint: disable=W0613