Disable startup sound when turning on my Macbook M1

Question

I am looking for a way to turn off that useless sound every time I open / turn on my Macbook. This is a Macbook Air (M1, 2020) currently on Big Sur 11.0.1

I already tried something without success:

• this script: https://github.com/matteoacrossi/nobootsound
• the simple command "sudo nvram SystemAudioVolume=%80"

Someone can help ??? Thank you !

Answer 1

There is a checkbox for it in System preferences:

https://www.howtogeek.com/700255/how-to-enable-or-disable-the-startup-sound-on-mac/