Merge "Fix prebuilt boot image hermetic build" into main

      for filename in ["kernel", "ramdisk", "vendor_ramdisk00"]:

        path = os.path.join(tmpdir, filename)

        if os.path.exists(path) and os.path.getsize(path):

          print("Using {} as salt for avb footer of {}".format(

              filename, partition_name))

          with open(path, "rb") as fp:

            salt = sha256(fp.read()).hexdigest()

            break

    AppendAVBSigningArgs(cmd, partition_name, salt)

    args = info_dict.get("avb_" + partition_name + "_add_hash_footer_args")

    if args and args.strip():