It appears that the firmware was written by Bosch and not VW themselves. I can't believe that only VW engineers were involved in writing the spec that was sent to Bosch and that only one of those engineers understood that "acoustic" really meant "emissions".
I would imagine that Robert Bosch GMBH and co. are quietly developing a war chest of cash right now. They appear to have been caught writing deliberately naughty code to order.
The firmware is ultra-generic but highly configurable. The default device isn't in the firmware itself.
Many different engine types will use the exact same firmware, the manufacture supplies a huge array of configuration values to make the ECU run the engine correctly.
All the firmware knows is that under some manufacture configurable situation, the engine will switch from one manufacture configurable mode of operation to another manufacture configurable mode of operation.
I would imagine that Robert Bosch GMBH and co. are quietly developing a war chest of cash right now. They appear to have been caught writing deliberately naughty code to order.