diff --git a/tools/build_api.py b/tools/build_api.py
index f7332fca28..9d8b954b43 100644
--- a/tools/build_api.py
+++ b/tools/build_api.py
@@ -458,8 +458,7 @@ def merge_region_list(region_list, destination, notify, padding=b'\xFF'):
         makedirs(dirname(destination))
     notify.info("Space used after regions merged: 0x%x" %
                 (merged.maxaddr() - merged.minaddr() + 1))
-    with open(destination, "wb+") as output:
-        merged.tofile(output, format=format.strip("."))
+    merged.tofile(destination, format=format.strip("."))
 
 def scan_resources(src_paths, toolchain, dependencies_paths=None,
                    inc_dirs=None, base_path=None, collect_ignores=False):
diff --git a/tools/memap.py b/tools/memap.py
index 7bc7fb190c..db043c5279 100644
--- a/tools/memap.py
+++ b/tools/memap.py
@@ -82,7 +82,7 @@ class _Parser(object):
 
 class _GccParser(_Parser):
     RE_OBJECT_FILE = re.compile(r'^(.+\/.+\.o)$')
-    RE_LIBRARY_OBJECT = re.compile(r'^.+' + sep + r'lib((.+\.a)\((.+\.o)\))$')
+    RE_LIBRARY_OBJECT = re.compile(r'^.+' + r''.format(sep) + r'lib((.+\.a)\((.+\.o)\))$')
     RE_STD_SECTION = re.compile(r'^\s+.*0x(\w{8,16})\s+0x(\w+)\s(.+)$')
     RE_FILL_SECTION = re.compile(r'^\s*\*fill\*\s+0x(\w{8,16})\s+0x(\w+).*$')
 
diff --git a/tools/notifier/term.py b/tools/notifier/term.py
index 55f49409bc..e8bb352d25 100644
--- a/tools/notifier/term.py
+++ b/tools/notifier/term.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from __future__ import print_function, division, absolute_import
+from past.builtins import basestring
 
 import re
 import sys
diff --git a/tools/test/examples/examples_lib.py b/tools/test/examples/examples_lib.py
index 8fda2d3f55..9b064cadc7 100644
--- a/tools/test/examples/examples_lib.py
+++ b/tools/test/examples/examples_lib.py
@@ -10,7 +10,6 @@ import os.path
 import sys
 import subprocess
 from shutil import rmtree
-from sets import Set
 
 ROOT = abspath(dirname(dirname(dirname(dirname(__file__)))))
 sys.path.insert(0, ROOT)
@@ -254,11 +253,11 @@ def export_repos(config, ides, targets, examples):
             ides - List of IDES to export to
     """
     results = {}
-    valid_examples = Set(examples)
+    valid_examples = set(examples)
     print("\nExporting example repos....\n")
     for example in config['examples']:
         example_names = [basename(x['repo']) for x in get_repo_list(example)]
-        common_examples = valid_examples.intersection(Set(example_names))
+        common_examples = valid_examples.intersection(set(example_names))
         if not common_examples:
             continue
         export_failures = []
@@ -337,11 +336,11 @@ def compile_repos(config, toolchains, targets, profile, examples):
 
     """
     results = {}
-    valid_examples = Set(examples)
+    valid_examples = set(examples)
     print("\nCompiling example repos....\n")
     for example in config['examples']:
         example_names = [basename(x['repo']) for x in get_repo_list(example)]
-        common_examples = valid_examples.intersection(Set(example_names))
+        common_examples = valid_examples.intersection(set(example_names))
         if not common_examples:
             continue
         failures = []
diff --git a/tools/test/memap/parse_test.py b/tools/test/memap/parse_test.py
index 92877ad8e2..6ed7ecd7e5 100644
--- a/tools/test/memap/parse_test.py
+++ b/tools/test/memap/parse_test.py
@@ -64,8 +64,6 @@ def test_parse_gcc():
         parsed_data_os_agnostic[k.replace('/', sep)] = PARSED_GCC_DATA[k]
 
     assert memap.modules == parsed_data_os_agnostic
-    memap.parse(join(dirname(__file__), "gcc.map"), "GCC_CR")
-    assert memap.modules == parsed_data_os_agnostic
 
 
 def test_add_empty_module():
diff --git a/tools/toolchains/__init__.py b/tools/toolchains/__init__.py
index ef4b3974f7..ead4707617 100644
--- a/tools/toolchains/__init__.py
+++ b/tools/toolchains/__init__.py
@@ -45,7 +45,7 @@ from ..memap import MemapParser
 CPU_COUNT_MIN = 1
 CPU_COEF = 1
 
-class LazyDict(dict):
+class LazyDict(object):
     def __init__(self):
         self.eager = {}
         self.lazy = {}
@@ -252,8 +252,6 @@ class Resources:
             headername = basename(filename)
             dupe_headers.setdefault(headername, set())
             dupe_headers[headername] |= set([headername])
-        for res in self.features.values():
-            res._collect_duplicates(dupe_dict, dupe_headers)
         return dupe_dict, dupe_headers
 
     def detect_duplicates(self, toolchain):