Technical: Why couldn't/hasn't a virus been created to attack ASICs?

1M Ago
Was watching a video about stuxnet etc.. I mean, btc miners are always online, that's the whole point. I don't know much about the technical aspects of bitcoin, just the basics, but it seems to me that, while taking down a few miners wouldn't hurt, and even a 51% attack would only cause problems til a rollback was implemented, a good virus could destroy the firmware of the chips themselves. Am I missing something?