[aDfbrtVt]

That may hold for a trivial device or a perfectly spec compliant device. However, the former is not interesting and the later does not exist. I agree that more test coverage would be beneficial, but I think your heavily downplaying the difficulty of writing realistic mock hardware.

[malkia]

Well in this case probably would've caught it, given debug mode, coverage. It's not even hw issue (AFAIT).