I don’t know what your situation is @xzhang, or if it’s the same as the user I replied to above. If we’re talking about Firmware upgrades only then you must have your seed if you currently have Firmware version 1.6.1.
Not to be difficult, but I can’t say a definite answer to you, because your two questions could be seen to be about two different things and your last question is too general. If I answered affirmative in this context it could easily be misunderstood for someone seeing your last question as a different case. For instance it could be interpreted as you’d only need your Recovery seed for possible Firmware upgrade fails in the future, which is not true.
So if you want a better answer you must give us more information about your situation for asking.
Edit: I see now that you’ve asked this in another thread too, but with more information. Note that my reply to you here is based on your questions in this thread. Please don’t ask about the same topic in different forum threads. Thank you.