Basically malware level tactics
It would be one thing if the download prominently said it would disable non HP ink right away.
But to put a time delayed booby trap in your firmware ... That has got to be a new all time low!
Really, what kind of evil bottom dweller thinks that's a great idea?
Welcome to nobody ever trusting your software / firmware or you ever again.
If they are so desperate for revenue they are stooping to tactics used by criminal scum, HP really needs to just go bankrupt.