They all run the same ECU and the same firmware on it, yeah. Teams can control some parameters though. It's to stop any kind of traction control.

Wow, crazy that all cars have to run the same firmware (sans parameter tweaking). I thought as an outsider to the sport that F1 was all about engineering the best possible car and putting the best possible driver in the seat, but the control systems engineer in me is sad that they're all stuck with the same control algorithms.