Set side B - Famicom Disk System and Nestopia

I’m using Nestopia to run Famicom Disk System games. I’m getting stuck when it says to set side B. It there a way to switch sides?

Try L1 button.

If I recall, first you need to eject (L1) and then swap side (L2).

I thought you had to eject, flip and reinsert the disk as well but I tested just the L1 button and it worked for me.

Thanks for the help. I didn’t realize there were additional functions mapped to buttons. I was looking for it in the core options menu. For anyone using a NES controller who comes across this thread, pressing “Q” on the keyboard will also swap sides.