This mod was not so easy to do. Biscuit use SMD (very small) components, and the mod needed an extra IC and few passive components. It was not only few wires and a switch, and it requires some soldering skills.
I should make a procedure one day, with pics and a schematic. But it takes time and I’m quite over-busy with the new products. More infos may come this year about this mod, I hope!