diff --git a/infra/bisector.py b/infra/bisector.py
index ff8366db7..f8d2e7d4f 100644
--- a/infra/bisector.py
+++ b/infra/bisector.py
@@ -32,9 +32,6 @@ This is done with the following steps:
 
 import argparse
 import collections
-import datetime
-from distutils import spawn
-import json
 import logging
 import os
 import sys
@@ -121,34 +118,6 @@ def main():
   return 0
 
 
-def _load_base_builder_repo():
-  """Get base-image digests."""
-  gcloud_path = spawn.find_executable('gcloud')
-  if not gcloud_path:
-    logging.warning('gcloud not found in PATH.')
-    return None
-
-  result, _, _ = utils.execute([
-      gcloud_path,
-      'container',
-      'images',
-      'list-tags',
-      'gcr.io/oss-fuzz-base/base-builder',
-      '--format=json',
-      '--sort-by=timestamp',
-  ],
-                               check_result=True)
-  result = json.loads(result)
-
-  repo = build_specified_commit.BaseBuilderRepo()
-  for image in result:
-    timestamp = datetime.datetime.fromisoformat(
-        image['timestamp']['datetime']).astimezone(datetime.timezone.utc)
-    repo.add_digest(timestamp, image['digest'])
-
-  return repo
-
-
 def _get_dedup_token(output):
   """Get dedup token."""
   for line in output.splitlines():
@@ -200,7 +169,7 @@ def _bisect(bisect_type, old_commit, new_commit, test_case_path, fuzz_target,
             build_data):
   """Perform the bisect."""
   # pylint: disable=too-many-branches
-  base_builder_repo = _load_base_builder_repo()
+  base_builder_repo = build_specified_commit.load_base_builder_repo()
 
   with tempfile.TemporaryDirectory() as tmp_dir:
     repo_url, repo_path = build_specified_commit.detect_main_repo(
diff --git a/infra/build_specified_commit.py b/infra/build_specified_commit.py
index 72c3bad8e..eef671b70 100644
--- a/infra/build_specified_commit.py
+++ b/infra/build_specified_commit.py
@@ -17,12 +17,17 @@ This module is allows each of the OSS Fuzz projects fuzzers to be built
 from a specific point in time. This feature can be used for implementations
 like continuious integration fuzzing and bisection to find errors
 """
+import argparse
 import bisect
+import datetime
+from distutils import spawn
 import os
 import collections
+import json
 import logging
 import re
 import shutil
+import tempfile
 import time
 
 import helper
@@ -152,6 +157,34 @@ def _build_image_with_retries(project_name):
   return result
 
 
+def get_required_post_checkout_steps(dockerfile_path):
+  """Get required post checkout steps (best effort)."""
+
+  checkout_pattern = re.compile(r'\s*RUN\s*(git|svn|hg)')
+
+  # If the build.sh is copied from upstream, we need to copy it again after
+  # changing the revision to ensure correct building.
+  post_run_pattern = re.compile(r'\s*RUN\s*(.*build\.sh.*(\$SRC|/src).*)')
+
+  with open(dockerfile_path) as handle:
+    lines = handle.readlines()
+
+  subsequent_run_cmds = []
+  for i, line in enumerate(lines):
+    if checkout_pattern.match(line):
+      subsequent_run_cmds = []
+      continue
+
+    match = post_run_pattern.match(line)
+    if match:
+      workdir = helper.workdir_from_lines(lines[:i])
+      command = match.group(1)
+      subsequent_run_cmds.append((workdir, command))
+
+  return subsequent_run_cmds
+
+
+# pylint: disable=too-many-locals
 def build_fuzzers_from_commit(commit,
                               build_repo_manager,
                               host_src_path,
@@ -175,8 +208,27 @@ def build_fuzzers_from_commit(commit,
     copy_src_from_docker(build_data.project_name,
                          os.path.dirname(host_src_path))
 
+  projects_dir = os.path.join('projects', build_data.project_name)
+  dockerfile_path = os.path.join(projects_dir, 'Dockerfile')
+
   for i in range(num_retry + 1):
     build_repo_manager.checkout_commit(commit, clean=False)
+
+    post_checkout_steps = get_required_post_checkout_steps(dockerfile_path)
+    for workdir, post_checkout_step in post_checkout_steps:
+      logging.info('Running post-checkout step `%s` in %s.', post_checkout_step,
+                   workdir)
+      helper.docker_run([
+          '-w',
+          workdir,
+          '-v',
+          host_src_path + ':' + '/src',
+          'gcr.io/oss-fuzz/' + build_data.project_name,
+          '/bin/bash',
+          '-c',
+          post_checkout_step,
+      ])
+
     result = helper.build_fuzzers_impl(project_name=build_data.project_name,
                                        clean=True,
                                        engine=build_data.engine,
@@ -191,7 +243,6 @@ def build_fuzzers_from_commit(commit,
     # Retry with an OSS-Fuzz builder container that's closer to the project
     # commit date.
     commit_date = build_repo_manager.commit_date(commit)
-    projects_dir = os.path.join('projects', build_data.project_name)
 
     # Find first change in the projects/<PROJECT> directory before the project
     # commit date.
@@ -216,8 +267,7 @@ def build_fuzzers_from_commit(commit,
     if base_builder_repo:
       base_builder_digest = base_builder_repo.find_digest(commit_date)
       logging.info('Using base-builder with digest %s.', base_builder_digest)
-      _replace_base_builder_digest(os.path.join(projects_dir, 'Dockerfile'),
-                                   base_builder_digest)
+      _replace_base_builder_digest(dockerfile_path, base_builder_digest)
 
     # Rebuild image and re-copy src dir since things in /src could have changed.
     if not _build_image_with_retries(build_data.project_name):
@@ -273,3 +323,80 @@ def detect_main_repo(project_name, repo_name=None, commit=None):
 
   logging.error('Failed to detect repo:\n%s', out)
   return None, None
+
+
+def load_base_builder_repo():
+  """Get base-image digests."""
+  gcloud_path = spawn.find_executable('gcloud')
+  if not gcloud_path:
+    logging.warning('gcloud not found in PATH.')
+    return None
+
+  result, _, _ = utils.execute([
+      gcloud_path,
+      'container',
+      'images',
+      'list-tags',
+      'gcr.io/oss-fuzz-base/base-builder',
+      '--format=json',
+      '--sort-by=timestamp',
+  ],
+                               check_result=True)
+  result = json.loads(result)
+
+  repo = BaseBuilderRepo()
+  for image in result:
+    timestamp = datetime.datetime.fromisoformat(
+        image['timestamp']['datetime']).astimezone(datetime.timezone.utc)
+    repo.add_digest(timestamp, image['digest'])
+
+  return repo
+
+
+def main():
+  """Main function."""
+  logging.getLogger().setLevel(logging.INFO)
+
+  parser = argparse.ArgumentParser(
+      description='Build fuzzers at a specific commit')
+  parser.add_argument('--project_name',
+                      help='The name of the project where the bug occurred.',
+                      required=True)
+  parser.add_argument('--commit',
+                      help='The newest commit SHA to be bisected.',
+                      required=True)
+  parser.add_argument('--engine',
+                      help='The default is "libfuzzer".',
+                      default='libfuzzer')
+  parser.add_argument('--sanitizer',
+                      default='address',
+                      help='The default is "address".')
+  parser.add_argument('--architecture', default='x86_64')
+
+  args = parser.parse_args()
+
+  repo_url, repo_path = detect_main_repo(args.project_name, commit=args.commit)
+
+  if not repo_url or not repo_path:
+    raise ValueError('Main git repo can not be determined.')
+
+  with tempfile.TemporaryDirectory() as tmp_dir:
+    host_src_dir = copy_src_from_docker(args.project_name, tmp_dir)
+    build_repo_manager = repo_manager.BaseRepoManager(
+        os.path.join(host_src_dir, os.path.basename(repo_path)))
+    base_builder_repo = load_base_builder_repo()
+
+    build_data = BuildData(project_name=args.project_name,
+                           engine=args.engine,
+                           sanitizer=args.sanitizer,
+                           architecture=args.architecture)
+    if not build_fuzzers_from_commit(args.commit,
+                                     build_repo_manager,
+                                     host_src_dir,
+                                     build_data,
+                                     base_builder_repo=base_builder_repo):
+      raise RuntimeError('Failed to build.')
+
+
+if __name__ == '__main__':
+  main()
diff --git a/infra/helper.py b/infra/helper.py
index 668f31d0b..22c81984d 100755
--- a/infra/helper.py
+++ b/infra/helper.py
@@ -363,13 +363,8 @@ def _env_to_docker_args(env_list):
 WORKDIR_REGEX = re.compile(r'\s*WORKDIR\s*([^\s]+)')
 
 
-def _workdir_from_dockerfile(project_name):
-  """Parse WORKDIR from the Dockerfile for the given project."""
-  dockerfile_path = get_dockerfile_path(project_name)
-
-  with open(dockerfile_path) as file_handle:
-    lines = file_handle.readlines()
-
+def workdir_from_lines(lines, default='/src'):
+  """Get the WORKDIR from the given lines."""
   for line in reversed(lines):  # reversed to get last WORKDIR.
     match = re.match(WORKDIR_REGEX, line)
     if match:
@@ -381,7 +376,17 @@ def _workdir_from_dockerfile(project_name):
 
       return os.path.normpath(workdir)
 
-  return os.path.join('/src', project_name)
+  return default
+
+
+def _workdir_from_dockerfile(project_name):
+  """Parse WORKDIR from the Dockerfile for the given project."""
+  dockerfile_path = get_dockerfile_path(project_name)
+
+  with open(dockerfile_path) as file_handle:
+    lines = file_handle.readlines()
+
+  return workdir_from_lines(lines, default=os.path.join('/src', project_name))
 
 
 def docker_run(run_args, print_output=True):