Roland micro cube bass rx

So I’ve been using my little 4 speaker Roland micro cube a lot recently, but today I discovered that the COSM bass amp sim knob no longer does anything.

This isn’t the biggest loss for me, but it does lose the octave effect, that I kinda like.

I was wondering if anyone else experienced this? I read the manual and tried to find a factory reset. The closest I found was maybe to hold down the tuner button and turn it on, but that had no effect.

Any advice?

It’s still quite functional as a practice amp for me.