diff --git a/.uncrustify.cfg b/.uncrustify.cfg
index 7ce0905..92b8ce9 100644
--- a/.uncrustify.cfg
+++ b/.uncrustify.cfg
@@ -19,8 +19,6 @@
 # limitations under the License.
 
 
-# Line length options
-
 # Wrap lines at 100 characters
 code_width = 100
 
diff --git a/scripts/code_style.py b/scripts/code_style.py
index 3958e87..dd8305f 100755
--- a/scripts/code_style.py
+++ b/scripts/code_style.py
@@ -1,9 +1,7 @@
 #!/usr/bin/env python3
 """Check or fix the code style by running Uncrustify.
 
-Note: The code style enforced by this script is not yet introduced to
-Mbed TLS. At present this script will only be used to prepare for a future
-change of code style.
+This script must be run from the root of a Git work tree containing Mbed TLS.
 """
 # Copyright The Mbed TLS Contributors
 # SPDX-License-Identifier: Apache-2.0
@@ -20,7 +18,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import argparse
-import io
 import os
 import re
 import subprocess
@@ -31,12 +28,10 @@
 CONFIG_FILE = ".uncrustify.cfg"
 UNCRUSTIFY_EXE = "uncrustify"
 UNCRUSTIFY_ARGS = ["-c", CONFIG_FILE]
-STDOUT_UTF8 = io.TextIOWrapper(sys.stdout.buffer, encoding='utf-8')
-STDERR_UTF8 = io.TextIOWrapper(sys.stderr.buffer, encoding='utf-8')
 CHECK_GENERATED_FILES = "tests/scripts/check-generated-files.sh"
 
 def print_err(*args):
-    print("Error: ", *args, file=STDERR_UTF8)
+    print("Error: ", *args, file=sys.stderr)
 
 # Match FILENAME(s) in "check SCRIPT (FILENAME...)"
 CHECK_CALL_RE = re.compile(r"\n\s*check\s+[^\s#$&*?;|]+([^\n#$&*?;|]+)",
@@ -69,8 +64,8 @@
                         "tests/suites/*.function",
                         "scripts/data_files/*.fmt"]
 
-    result = subprocess.run(git_ls_files_cmd, stdout=subprocess.PIPE, \
-            stderr=STDERR_UTF8, check=False)
+    result = subprocess.run(git_ls_files_cmd, stdout=subprocess.PIPE,
+                            check=False)
 
     if result.returncode != 0:
         print_err("git ls-files returned: " + str(result.returncode))
@@ -90,8 +85,9 @@
     """
     Get the version string from Uncrustify
     """
-    result = subprocess.run([UNCRUSTIFY_EXE, "--version"], \
-            stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=False)
+    result = subprocess.run([UNCRUSTIFY_EXE, "--version"],
+                            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                            check=False)
     if result.returncode != 0:
         print_err("Could not get Uncrustify version:", str(result.stderr, "utf-8"))
         return ""
@@ -106,26 +102,25 @@
     style_correct = True
     for src_file in src_file_list:
         uncrustify_cmd = [UNCRUSTIFY_EXE] + UNCRUSTIFY_ARGS + [src_file]
-        result = subprocess.run(uncrustify_cmd, stdout=subprocess.PIPE, \
-                stderr=subprocess.PIPE, check=False)
+        result = subprocess.run(uncrustify_cmd, stdout=subprocess.PIPE,
+                                stderr=subprocess.PIPE, check=False)
         if result.returncode != 0:
-            print_err("Uncrustify returned " + str(result.returncode) + \
-                    " correcting file " + src_file)
+            print_err("Uncrustify returned " + str(result.returncode) +
+                      " correcting file " + src_file)
             return False
 
         # Uncrustify makes changes to the code and places the result in a new
         # file with the extension ".uncrustify". To get the changes (if any)
         # simply diff the 2 files.
         diff_cmd = ["diff", "-u", src_file, src_file + ".uncrustify"]
-        result = subprocess.run(diff_cmd, stdout=subprocess.PIPE, \
-                stderr=STDERR_UTF8, check=False)
-        if len(result.stdout) > 0:
-            print(src_file + " - Incorrect code style.", file=STDOUT_UTF8)
-            print("File changed - diff:", file=STDOUT_UTF8)
-            print(str(result.stdout, "utf-8"), file=STDOUT_UTF8)
+        cp = subprocess.run(diff_cmd, check=False)
+
+        if cp.returncode == 1:
+            print(src_file + " changed - code style is incorrect.")
             style_correct = False
-        else:
-            print(src_file + " - OK.", file=STDOUT_UTF8)
+        elif cp.returncode != 0:
+            raise subprocess.CalledProcessError(cp.returncode, cp.args,
+                                                cp.stdout, cp.stderr)
 
         # Tidy up artifact
         os.remove(src_file + ".uncrustify")
@@ -139,12 +134,11 @@
     code_change_args = UNCRUSTIFY_ARGS + ["--no-backup"]
     for src_file in src_file_list:
         uncrustify_cmd = [UNCRUSTIFY_EXE] + code_change_args + [src_file]
-        result = subprocess.run(uncrustify_cmd, check=False, \
-                stdout=STDOUT_UTF8, stderr=STDERR_UTF8)
+        result = subprocess.run(uncrustify_cmd, check=False)
         if result.returncode != 0:
-            print_err("Uncrustify with file returned: " + \
-                    str(result.returncode) + " correcting file " + \
-                    src_file)
+            print_err("Uncrustify with file returned: " +
+                      str(result.returncode) + " correcting file " +
+                      src_file)
             return False
     return True
 
@@ -160,7 +154,7 @@
     # Guard against future changes that cause the codebase to require
     # more passes.
     if not check_style_is_correct(src_file_list):
-        print("Code style still incorrect after second run of Uncrustify.")
+        print_err("Code style still incorrect after second run of Uncrustify.")
         return 1
     else:
         return 0
@@ -172,9 +166,9 @@
     uncrustify_version = get_uncrustify_version().strip()
     if UNCRUSTIFY_SUPPORTED_VERSION not in uncrustify_version:
         print("Warning: Using unsupported Uncrustify version '" +
-              uncrustify_version + "'", file=STDOUT_UTF8)
+              uncrustify_version + "'")
         print("Note: The only supported version is " +
-              UNCRUSTIFY_SUPPORTED_VERSION, file=STDOUT_UTF8)
+              UNCRUSTIFY_SUPPORTED_VERSION)
 
     parser = argparse.ArgumentParser()
     parser.add_argument('-f', '--fix', action='store_true',
@@ -203,6 +197,7 @@
     else:
         # Check mode
         if check_style_is_correct(src_files):
+            print("Checked {} files, style ok.".format(len(src_files)))
             return 0
         else:
             return 1