Calibrating a Gen 2 controller with a Gen 1 Brain

We had a Gen 2 controller lined to a Gen 1 brain. It worked fine for a while, but at a certain point, it needed to be calibrated. We couldn’t figure out how to do it, as when we selected the calibration, it told us it required to be tethered. Any ideas?

I’m not sure that’s possible, I’ll check when I get back after the long weekend.