>If it was added after they started selling it

While it's great we're getting the manufactures to just stop sending out straight malware and it should be stopped the next most obvious means of attack is just having the device update and add superaids to it's new functionality.

So, no, it won't stop 99% of it at all.

And honestly this isn't that much different from what US companies are already great at by providing updates that take away features we bought with the device.

And not just updating really doesn't save you, instead of being part of a factory botnet, you're just open to become part of some other botnet.