patched DLC should work just fine in OFW via data transfer, PSN and other homebrews dont (unless it was patched to run in CFW 4.21), latest multiman will run OFW but will error something that related with invalid firmware, but yes you can play games on it by using direct boot. Showtime also works on it.
to be short, anything that is signed under 4.21CFW or above will work also on OFW. Sony cant block their own private keys. Although they manage to block geohot's NPDRM pseudo-signing keys, so who knows maybe they can block it too in the future.