diff --git a/bob/buildout/envwrapper.py b/bob/buildout/envwrapper.py
index ab432e24dc06be6921bc53436762a721f87b864f..e21020ebbe2453022b69306f26d41e72f5eef4ae 100644
--- a/bob/buildout/envwrapper.py
+++ b/bob/buildout/envwrapper.py
@@ -23,10 +23,8 @@ class EnvironmentWrapper(object):
   settings from initialization.
   """
 
-  # Note: CLang does not work well with BZ_DEBUG
-  # 24.01.2017: we only support gcc on both Linux and MacOSX
+  # 30.01.2017: we only set debug flags, release flags are set by toolchain
   DEBUG_CFLAGS = '-O0 -g -DBOB_DEBUG -DBZ_DEBUG'
-  RELEASE_CFLAGS = '-O3 -g0 -DNDEBUG -mtune=generic'
 
   def __init__(self, logger, debug=None, prefixes=None, environ=None):
 
@@ -85,7 +83,6 @@ class EnvironmentWrapper(object):
     # reset the CFLAGS and CXXFLAGS depending on the user input
     cflags = None
     if self.debug is True: cflags = str(EnvironmentWrapper.DEBUG_CFLAGS)
-    elif self.debug is False: cflags = str(EnvironmentWrapper.RELEASE_CFLAGS)
     # else: pass
 
     def _order_flags(key, internal=None):
diff --git a/bob/buildout/test_envwrapper.py b/bob/buildout/test_envwrapper.py
index fdead08cea5466f8abd261ef7209539f3d0f2607..15052e6abf62587f0783b05c997af59346d20555 100644
--- a/bob/buildout/test_envwrapper.py
+++ b/bob/buildout/test_envwrapper.py
@@ -58,10 +58,8 @@ def test_set_debug_true():
 
   assert 'CFLAGS' in os.environ
   assert os.environ['CFLAGS'].find(EnvironmentWrapper.DEBUG_CFLAGS) >= 0
-  assert os.environ['CFLAGS'].find(EnvironmentWrapper.RELEASE_CFLAGS) < 0
   assert 'CXXFLAGS' in os.environ
   assert os.environ['CXXFLAGS'].find(EnvironmentWrapper.DEBUG_CFLAGS) >= 0
-  assert os.environ['CXXFLAGS'].find(EnvironmentWrapper.RELEASE_CFLAGS) < 0
 
   e.unset()
   for key in before:
@@ -83,16 +81,10 @@ def test_set_debug_false():
 
   e.set()
 
-  nose.tools.eq_(len(os.environ) - len(before), 2)
+  nose.tools.eq_(len(os.environ) - len(before), 0)
 
-  assert 'CFLAGS' in os.environ
-  assert 'CXXFLAGS' in os.environ
-  nose.tools.eq_(os.environ['CFLAGS'], e.environ['CFLAGS'])
-  assert os.environ['CFLAGS'].find(EnvironmentWrapper.DEBUG_CFLAGS) < 0
-  assert os.environ['CFLAGS'].find(EnvironmentWrapper.RELEASE_CFLAGS) >= 0
-  nose.tools.eq_(os.environ['CXXFLAGS'], e.environ['CXXFLAGS'])
-  assert os.environ['CXXFLAGS'].find(EnvironmentWrapper.DEBUG_CFLAGS) < 0
-  assert os.environ['CXXFLAGS'].find(EnvironmentWrapper.RELEASE_CFLAGS) >= 0
+  assert 'CFLAGS' not in os.environ
+  assert 'CXXFLAGS' not in os.environ
 
   e.unset()
   for key in before: