diff --git a/scripts/code_size_compare.py b/scripts/code_size_compare.py
index 8ed5f9cd63..171aafeec3 100755
--- a/scripts/code_size_compare.py
+++ b/scripts/code_size_compare.py
@@ -190,7 +190,7 @@ class CodeSizeBuildInfo: # pylint: disable=too-few-public-methods
         self.compiler = size_dist_info.compiler
         self.opt_level = size_dist_info.opt_level
 
-        self.make_cmd = ['make', '-j', 'lib']
+        self.make_cmd = ['make', '-f', './scripts/legacy.make', '-j', 'lib']
 
         self.host_arch = host_arch
         self.logger = logger
@@ -287,7 +287,7 @@ class CodeSizeCalculator:
         """
         self.repo_path = "."
         self.git_command = "git"
-        self.make_clean = 'make clean'
+        self.make_clean = 'make -f ./scripts/legacy.make clean'
 
         self.git_rev = git_rev
         self.pre_make_cmd = pre_make_cmd
@@ -319,6 +319,10 @@ class CodeSizeCalculator:
                  git_worktree_path, self.git_rev], cwd=self.repo_path,
                 stderr=subprocess.STDOUT
             )
+            subprocess.check_output(
+                [self.git_command, "submodule", "update", "--init", "--recursive"],
+                cwd=git_worktree_path, stderr=subprocess.STDOUT
+            )
 
         return git_worktree_path