Mindboards

Well perhaps the function intended in the firmware is not "turn both motors of 400 degree", but "turn both motors, with a given speed ratio, until one of them turned 400 degree".

Actually, it is a feature !

not exactly: it has to be understood as "turn both motors, with a given speed ratio, in synchronized mode until the encoder target has been reached"
what means that all motors have to approximate the encoder target.
But maybe you could fix the bug in the recompiled version?

This is all pretty clear with the turn ratio set to -100. But what about when it's set to 30? How do the motors respond then?

And we were talking about other firmwares acting the same. But, what if they accept different parameters? I'm not sure if it's changed, but when RobotC was first written, instead of having two motors with one turn value, it had one master motor and one slave motor. The turn value would be a number from 100 to -100, where 100 was "same speed as master", 0 was "stop" and -100 was "opposite direction of master, same speed". So, a value of 0 was totally different.

We can spend lots of time talking about how we think John should spend his time to make things better for us. But, I'm content that the work-around that he posted solves the problem for me.

Thanks
Steve