Let’s assume the manufacturer actually disabled your brakes with an update or someone cut you break lines clean through and you then still drive around… The driver is at fault. You can not drive around with an unsafe vehicle just because someone else made it so, instead of actively doing it yourself. This goes as far as not noticing that your breaks are simply worn out (loud noise or light on the dash): You are absolutely liable if you fail to notice this.

With the manipulation it would be different if that would happen while driving, for obvious reasons.

Generally if you are putting others at risk because you do something: You are liable.