Recovery mode is DFU mode. What happened is that your jailbreak is probably tethered and you just have to redo the jailbreak to start it up again. A tethered jailbreak means that when you restart the iPod, which it does after updating, it will go in to recovery mode until you jailbreak again. If you used redsn0w, open it then check the "just boot tethered". If you used something else, just redo it.