You did all right. Make gpt table with fat32 and copy all data from iso on it. But you also need to set flag "msftdata"(not "boot") on this partition with e.g. parted.
You did all right. Make gpt table with fat32 and copy all data from iso on it. But you also need to set flag "msftdata"(not "boot") on this partition with e.g. parted.