diff --git a/build-buildroot b/build-buildroot
index 9cd16b2..f2f1375 100755
--- a/build-buildroot
+++ b/build-buildroot
@@ -84,7 +84,7 @@ usually extra Buildroot targets.
         elif self.env['arch'] == 'aarch64':
             defconfig = 'qemu_aarch64_virt_defconfig'
         br2_external_dirs = []
-        for package_dir in os.listdir(self.env['packages_dir']):
+        for package_dir in sorted(os.listdir(self.env['packages_dir'])):
             package_dir_abs = os.path.join(self.env['packages_dir'], package_dir)
             if os.path.isdir(package_dir_abs):
                 br2_external_dirs.append(self._path_relative_to_buildroot(package_dir_abs))
diff --git a/common.py b/common.py
index 2df3d29..609b2c2 100644
--- a/common.py
+++ b/common.py
@@ -866,7 +866,10 @@ lunch aosp_{}-eng
         List checkpoint directory, oldest first.
         '''
         prefix_re = re.compile(self.env['gem5_cpt_prefix'])
-        files = list(filter(lambda x: os.path.isdir(os.path.join(self.env['m5out_dir'], x)) and prefix_re.search(x), os.listdir(self.env['m5out_dir'])))
+        files = list(filter(
+            lambda x: os.path.isdir(os.path.join(self.env['m5out_dir'], x))
+                      and prefix_re.search(x), os.listdir(self.env['m5out_dir'])
+        ))
         files.sort(key=lambda x: os.path.getmtime(os.path.join(self.env['m5out_dir'], x)))
         return files
 
diff --git a/release-zip b/release-zip
index 5139b40..2bb2477 100755
--- a/release-zip
+++ b/release-zip
@@ -20,9 +20,9 @@ https://github.com/cirosantilli/linux-kernel-module-cheat#release-zip
     def timed_main(self):
         self.zip_files.append(self.env['qcow2_file'])
         self.zip_files.append(self.env['linux_image'])
-        for root, dirs, files in os.walk(self.env['baremetal_build_dir']):
-            for file in files:
-                path = os.path.join(root, file)
+        for root, dirnames, filenames in os.walk(self.env['baremetal_build_dir']):
+            for filename in sorted(filenames):
+                path = os.path.join(root, filename)
                 if os.path.splitext(path)[1] == self.env['baremetal_build_ext']:
                     self.zip_files.append(path)
 
diff --git a/shell_helpers.py b/shell_helpers.py
index 58790ba..a893112 100644
--- a/shell_helpers.py
+++ b/shell_helpers.py
@@ -122,7 +122,7 @@ class ShellHelpers:
     def copy_dir_if_update_non_recursive(self, srcdir, destdir, filter_ext=None):
         # TODO print rsync equivalent.
         os.makedirs(destdir, exist_ok=True)
-        for basename in os.listdir(srcdir):
+        for basename in sorted(os.listdir(srcdir)):
             src = os.path.join(srcdir, basename)
             if os.path.isfile(src):
                 noext, ext = os.path.splitext(basename)
@@ -138,6 +138,7 @@ class ShellHelpers:
         srcdir_abs = os.path.abspath(srcdir)
         srcdir_abs_len = len(srcdir_abs)
         for path, dirnames, filenames in os.walk(srcdir_abs):
+            dirnames.sort()
             for dirname in dirnames:
                 dirpath = os.path.join(path, dirname)
                 dirpath_relative_root = dirpath[srcdir_abs_len + 1:]
diff --git a/test-baremetal b/test-baremetal
index ad5a467..bfb19fd 100755
--- a/test-baremetal
+++ b/test-baremetal
@@ -26,14 +26,15 @@ If given, run only the given tests. Otherwise, run all tests.
         if self.env['tests'] == []:
             baremetal_source_exts = (self.env['c_ext'], self.env['asm_ext'])
             paths = []
-            for f in os.listdir(self.env['baremetal_source_dir']):
+            for f in sorted(os.listdir(self.env['baremetal_source_dir'])):
                 path = os.path.join(self.env['baremetal_source_dir'], f)
                 if os.path.isfile(path) and os.path.splitext(path)[1] in baremetal_source_exts:
                     paths.append(path)
-            for root, dirs, files in os.walk(self.env['baremetal_source_arch_dir'], topdown=True):
-                dirs[:] = [d for d in dirs if d != 'interactive']
-                for file in files:
-                    path = os.path.join(root, file)
+            for root, dirnames, filenames in os.walk(self.env['baremetal_source_arch_dir'], topdown=True):
+                dirnames[:] = [d for d in dirnames if d != 'interactive']
+                dirnames.sort()
+                for filename in filenames:
+                    path = os.path.join(root, filename)
                     if os.path.splitext(path)[1] in baremetal_source_exts:
                         paths.append(path)
             sources = []
diff --git a/test-gdb b/test-gdb
index 1590abf..0932044 100755
--- a/test-gdb
+++ b/test-gdb
@@ -27,13 +27,13 @@ found by searching for the Python test files.
         if self.env['arch'] in self.env['crosstool_ng_supported_archs']:
             if self.env['tests'] == []:
                 test_scripts_noext = []
-                for f in os.listdir(self.env['baremetal_source_dir']):
-                    base, ext = os.path.splitext(f)
+                for filename in sorted(os.listdir(self.env['baremetal_source_dir'])):
+                    base, ext = os.path.splitext(filename)
                     if ext == '.py':
                         test_scripts_noext.append(base)
-                for root, dirs, files in os.walk(os.path.join(self.env['baremetal_source_dir'], 'arch', self.env['arch'])):
-                    for f in files:
-                        base, ext = os.path.splitext(f)
+                for root, dirnames, filenames in os.walk(os.path.join(self.env['baremetal_source_dir'], 'arch', self.env['arch'])):
+                    for filename in filenames:
+                        base, ext = os.path.splitext(filename)
                         if ext == '.py':
                             full_path = os.path.join(root, base)
                             relpath = os.path.relpath(full_path, self.env['baremetal_source_dir'])