diff --git a/tools/dev/v8gen.py b/tools/dev/v8gen.py
index 18abf8aa25..c6ba1d2174 100755
--- a/tools/dev/v8gen.py
+++ b/tools/dev/v8gen.py
@@ -121,7 +121,7 @@ class GenerateGnArgs(object):
     add_common_options(list_cmd)
 
     # Default to "gen" unless global help is requested.
-    if not args or args[0] not in subps.choices.keys() + ['-h', '--help']:
+    if not args or args[0] not in list(subps.choices) + ['-h', '--help']:
       args = ['gen'] + args
 
     return self.parser.parse_args(args)
@@ -193,14 +193,16 @@ class GenerateGnArgs(object):
     return 0
 
   def verbose_print_1(self, text):
-    if self._options.verbosity >= 1:
+    if self._options.verbosity and self._options.verbosity >= 1:
       print('#' * 80)
       print(text)
 
   def verbose_print_2(self, text):
-    if self._options.verbosity >= 2:
+    if self._options.verbosity and self._options.verbosity >= 2:
       indent = ' ' * 2
       for l in text.splitlines():
+        if type(l) == bytes:
+          l = l.decode()
         print(indent + l)
 
   def _call_cmd(self, args):
@@ -306,7 +308,7 @@ if __name__ == "__main__":
   try:
     sys.exit(gen.main())
   except Exception:
-    if gen._options.verbosity < 2:
+    if not gen._options.verbosity or gen._options.verbosity < 2:
       print ('\nHint: You can raise verbosity (-vv) to see the output of '
              'failed commands.\n')
     raise
diff --git a/tools/mb/mb.py b/tools/mb/mb.py
index 9d81453a4c..7031ba50db 100755
--- a/tools/mb/mb.py
+++ b/tools/mb/mb.py
@@ -878,7 +878,7 @@ class MetaBuildWrapper(object):
     return err, labels
 
   def GNCmd(self, subcommand, path, *args):
-    if self.platform == 'linux2':
+    if self.platform.startswith('linux'):
       subdir, exe = 'linux64', 'gn'
     elif self.platform == 'darwin':
       subdir, exe = 'mac', 'gn'
diff --git a/tools/testrunner/base_runner.py b/tools/testrunner/base_runner.py
index 28a177e385..a03080cee3 100644
--- a/tools/testrunner/base_runner.py
+++ b/tools/testrunner/base_runner.py
@@ -358,7 +358,7 @@ class BaseTestRunner(object):
 
     # Progress
     parser.add_option("-p", "--progress",
-                      choices=PROGRESS_INDICATORS.keys(), default="mono",
+                      choices=list(PROGRESS_INDICATORS), default="mono",
                       help="The style of progress indicator (verbose, dots, "
                            "color, mono)")
     parser.add_option("--json-test-results",
diff --git a/tools/testrunner/local/statusfile.py b/tools/testrunner/local/statusfile.py
index 6c2cc01fb8..b6f97cd564 100644
--- a/tools/testrunner/local/statusfile.py
+++ b/tools/testrunner/local/statusfile.py
@@ -282,7 +282,7 @@ def ReadStatusFile(content, variables):
 
 def _ReadSection(section, variables, rules, prefix_rules):
   assert type(section) == dict
-  for rule, outcome_list in section.iteritems():
+  for rule, outcome_list in section.items():
     assert type(rule) == str
 
     if rule[-1] == '*':