Firmware validation fails randomly

[Jim Cheetham]

I've been using a Philips monitor recently with a MacBook, with a built-in
hub that I've connected some devices to. Most of them seem to be fine - my
keyboard for example. One of them, a logitech dongle connecting to a
trackball mouse, is really really unreliable - every now and then I simply
don't get mouse movements, or they're very stuttery (if that's a word).
Whatever the interference is, it seems to last for 10-15 seconds or so, and
then settles down and is good for another couple of hours.

I didn't spend a lot of time trying to characterise the issue; I moved the
dongle down to a small powered hub that was also connected to the monitor,
thinking that perhaps it was an RF issue, but that didn't help. Now the
dongle lives plugged directly in to one of my two usb-c ports on the mac,
and it's totally reliable.

Being a mac, I also haven't bothered trying to track down error messages to
inform me what's going on.

So I guess I can say that at least *some* usb hubs in monitors do lead to
some instability for some devices and not others; but the frequency I
observed doesn't sound like it's often enough to account for your
observations completely.

On a practical front, verifying the firmware is mostly a protection against
supply-chain interference; once the device is in your possession it's
unlikely to be the target of physical attack, there are other more valuable
targets available to them at that time ...

So although we have included a validate-every-startup step in the scripts,
it's not adding much value to your security posture. If you have no other
worries about the device in operation, perhaps the convenience value of the
monitor's hub outweighs the need to validate the firmware on an ongoing
basis?

-jim
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