changing wheel diameter in the computer on tha rise

[Cavi]

So, I am running 27.5 wheels on my wife's rise and I know many here have done a mullet setup. Does anyone know how to change the wheel diameter in the computer so that the speedo will read correct? Orbea says it is not possible on the RS, I find that hard to believe

 

[soundwave]

One can do that via Emax app for example