"The team's attack works by replacing the FTDI DLL"
That DLL (a driver for the USB hardware interface used) is on the engineer's computer, presumably translating "airbag disabled" into "airbag enabled" messages as it receives them and passes them on.
Only that and other tampered with PCs will do that. The car is still reporting the airbags are disabled and PCs not tampered with will show that.
They haven't 'hacked the car'; only modified the PC to silently disable the airbag and have it reporting the wrong status.
Biting the hand that feeds IT
