diff --git a/script/lib/git.py b/script/lib/git.py
index cc82ec9c1076..0edcd98ea025 100644
--- a/script/lib/git.py
+++ b/script/lib/git.py
@@ -47,7 +47,7 @@ def get_repo_root(path):
 
 
 def am(repo, patch_data, threeway=False, directory=None, exclude=None,
-    committer_name=None, committer_email=None):
+    committer_name=None, committer_email=None, keep_cr=True):
   args = []
   if threeway:
     args += ['--3way']
@@ -56,6 +56,10 @@ def am(repo, patch_data, threeway=False, directory=None, exclude=None,
   if exclude is not None:
     for path_pattern in exclude:
       args += ['--exclude', path_pattern]
+  if keep_cr is True:
+    # Keep the CR of CRLF in case any patches target files with Windows line
+    # endings.
+    args += ['--keep-cr']
 
   root_args = ['-C', repo]
   if committer_name is not None:
@@ -230,7 +234,9 @@ def split_patches(patch_data):
   """Split a concatenated series of patches into N separate patches"""
   patches = []
   patch_start = re.compile('^From [0-9a-f]+ ')
-  for line in patch_data.splitlines():
+  # Keep line endings in case any patches target files with CRLF.
+  keep_line_endings = True
+  for line in patch_data.splitlines(keep_line_endings):
     if patch_start.match(line):
       patches.append([])
     patches[-1].append(line)
@@ -246,13 +252,23 @@ def munge_subject_to_filename(subject):
 
 def get_file_name(patch):
   """Return the name of the file to which the patch should be written"""
+  file_name = None
   for line in patch:
     if line.startswith('Patch-Filename: '):
-      return line[len('Patch-Filename: '):]
+      file_name = line[len('Patch-Filename: '):]
+      break
   # If no patch-filename header, munge the subject.
-  for line in patch:
-    if line.startswith('Subject: '):
-      return munge_subject_to_filename(line[len('Subject: '):])
+  if not file_name:
+    for line in patch:
+      if line.startswith('Subject: '):
+        file_name = munge_subject_to_filename(line[len('Subject: '):])
+        break
+  return file_name.rstrip('\n')
+
+
+def join_patch(patch):
+  """Joins and formats patch contents"""
+  return ''.join(remove_patch_filename(patch)).rstrip('\n') + '\n'
 
 
 def remove_patch_filename(patch):
@@ -294,10 +310,8 @@ def export_patches(repo, out_dir, patch_range=None, dry_run=False):
     for patch in patches:
       filename = get_file_name(patch)
       filepath = posixpath.join(out_dir, filename)
-      existing_patch = io.open(filepath, 'r', encoding='utf-8').read()
-      formatted_patch = (
-        '\n'.join(remove_patch_filename(patch)).rstrip('\n') + '\n'
-      )
+      existing_patch = io.open(filepath, 'rb').read()
+      formatted_patch = join_patch(patch)
       if formatted_patch != existing_patch:
         patch_count += 1
     if patch_count > 0:
@@ -322,12 +336,11 @@ def export_patches(repo, out_dir, patch_range=None, dry_run=False):
       for patch in patches:
         filename = get_file_name(patch)
         file_path = posixpath.join(out_dir, filename)
-        formatted_patch = (
-          '\n'.join(remove_patch_filename(patch)).rstrip('\n') + '\n'
-        )
+        formatted_patch = join_patch(patch)
+        # Write in binary mode to retain mixed line endings on write.
         with io.open(
-          file_path, 'w', newline='\n', encoding='utf-8'
+          file_path, 'wb'
         ) as f:
-          f.write(formatted_patch)
+          f.write(formatted_patch.encode('utf-8'))
         pl.write(filename + '\n')
 
diff --git a/script/lint.js b/script/lint.js
index 70f6a51693f7..a194aacb7b76 100755
--- a/script/lint.js
+++ b/script/lint.js
@@ -207,7 +207,7 @@ const LINTERS = [{
         console.warn(`Patch file '${f}' has no description. Every patch must contain a justification for why the patch exists and the plan for its removal.`);
         return false;
       }
-      const trailingWhitespace = patchText.split('\n').filter(line => line.startsWith('+')).some(line => /\s+$/.test(line));
+      const trailingWhitespace = patchText.split(/\r?\n/).some(line => line.startsWith('+') && /\s+$/.test(line));
       if (trailingWhitespace) {
         console.warn(`Patch file '${f}' has trailing whitespace on some lines.`);
         return false;