CV Calibration not working properly?

Does anyone know how to do this? The manual says to start the pyramid while holding down encoder 5 to enter cv calibration mode, but I do this and it just powers up as normal. I tried holding encoder 4 and powering up and I got a page that says CV in the top left but then it doesn’t respond like the manual says it should, nothing happens at all. I’m on OS 2.30 on an mk1.