Hi Dave.
Maybe is not exactly what you are looking for, but I have made some modification on my B9 ( https://www.ehx.com/forums/viewthread/10197/ ) and I believe that the part related to the Dry/Mute function could help.
Have a look…

Hi Carl.

You’re asking a lot… I hope EHX could do it!
I’ve made a much more simple modification to my B9 to have an OLED display and some other features.

Have a look at https://www.ehx.com/forums/viewthread/10197/

If you’re familiar with Arduino and instructables you can DIY https://www.instructables.com/id/B9/

Enjoy!