I'm starting from a cold & dark panel, switch on the batteries, followed by external power and confirm with OIS that I have GPU connected. Then once I'm done setting up the aircraft and start preparing for departure, I switch on the APU followed by the beacon switch, at which point the aircraft powers down completely. Both batteries and external power goes off, the OIS screen goes blank, and I get alerts on the hydraulic system.
Please ignore the ongoing IRS alignment, as it was just a quick dive in to get the screenshots, and the position of the throttles, I haven't calibrated it in the -900 yet as I wanted to fly the -1000 first.