diff --git a/tools/test-case-generators/generate-all-test-cases b/tools/test-case-generators/generate-all-test-cases
index 3293cc0bf..7337a67f1 100755
--- a/tools/test-case-generators/generate-all-test-cases
+++ b/tools/test-case-generators/generate-all-test-cases
@@ -1290,9 +1290,9 @@ class ManifestTestCaseMatrixGenerator(BaseTestCaseMatrixGenerator):
                     script_dir = os.path.dirname(__file__)
                     log.info("Generating manifest for %s-%s-%s", distro_name, arch_name, image_type)
                     try:
-                        subprocess.check_call([f"{script_dir}/generate-test-cases", "--distro", f"{distro_name}", "--arch",
+                        subprocess.run([f"{script_dir}/generate-test-cases", "--distro", f"{distro_name}", "--arch",
                             f"{arch_name}", "--image-types", f"{image_type}", "--store", "/dev/null", "--output", f"{self.output}",
-                            "--keep-image-info"], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+                            "--keep-image-info"], stdout=subprocess.PIPE, stderr=subprocess.PIPE, check=True, encoding="utf-8")
                     except subprocess.CalledProcessError as e:
                         log.error("Generating manifest for %s-%s-%s FAILED: %s", distro_name, arch_name, image_type, e)