It's been a while since I had a processor in my setup but doesn't power on via switch put unit into standby? If so, to bring unit out of standby you just press source button on MSR and it go to that input.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).