#!/bin/sh # this needs to be ran as proper root (> su) # remove immutable flag chattr -i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82 # macos terminal uses BELL code (0x07) to audibly play system messages/warnings (such as the startup chime # that simply confirms POST was successful and lets everyone else in the room know as well) so set it to null printf "\x07\x00\x00\x00\x00" > /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82 # replace immutable flag chattr +i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82