the ECU DOESN'T CONTROL the boost, its there as a safe guard! If things get too hot it reduces the boost until things calm down.

The AMAL is fed with an unfused 12v ignition feed, the ecu switches the earth.

Go to your car, turn the ignition on and listen for the amal clicking a few times, its not theory, its fact!

I believe there are chips around that can use the AMAL to control boost though, Stu's Evolution chips i believe are one of them.