At which point you would roll back to the previous firmware, because of course we're going to keep copies. This sounds like a horrifically ineffective plan. We're certainly better off having fifth gen fighters with that incredibly minimal risk attached than we are with fourth gen fighters that are completely outclassed.

And again, if we're at the point where potential hostilities are close enough that a one month timebomb could matter then we're at the point where we're not loading any software the US sends us.

The far more meaningful risk here is that they can simply stop giving us new parts and software updates. That's actually a real and valid concern.