Weird issues

let me start by saying hello, im a new user here…thanks for having a greet interface to get help and be part of the development process. My issues are these: for starters i wanted to switch firmware from ardupilot to px4.(proficnc adsb carrier + cube orange). I started out with mission planner, not realizing it was flashing ardupilot not px4, so i switched it over to Qgroundcontrol. when i try and flash px4 through qgcs it gives me “Unable to find specified firmware for board type” all the data comes through from the flight controller but im unable to flash new px4. secondly when i start the flightcontroller either powered by usb or battery - i dont get the usual trill of sounds once the fc comes online…i get three tones sequentially, evenly spaced, and downward in tone. does anyone know where i can find descriptions of startup sounds? i came across one, but there wasnt a sample that sounded anything like mine.
Thanks in advance for any insight!