How to Mute Macbook Startup Chime from Linux

General system Newbie
1

I’m working my way through installing EndeavourOS on a 2011 Macbook Air which has been totally erased from our ISO install (which has given new life to this beauty). Since I had also wiped the NVRAM settings of the laptop the startup sound would chime every cold boot or restart which can be disturbing.

Below are my notes on how to do this (which I tested). Thought best to share here just in case anyone else has recommendations (as I primarily roll with Lenovo).

How to Mute Macbook Startup Chime from Linux

The following steps will allow you to mute the Apple startup chime when cold booting or restarting your Apple device. This was tested on an 2011 Macbook Air.

  1. Install efivar utility:
sudo pacman -S efivar
  1. Switch to root:
sudo su
  1. Set Chime setting to be editable:
sudo chattr -i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82
  1. Set the Chime value to mute:
sudo printf "\x07\x00\x00\x00\x00" > /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82
  1. Set Chime setting to read-only again.
sudo chattr +i /sys/firmware/efi/efivars/SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82

Note:

  • You can use the key combination of <Command + Option + P + R> to reset the Apple\Macbook NVRAM to reset this setting.

Source:

#apple #sound

2

Not sure if this is helpful to anyone, but on both my 2011 MacBook Pro laptop and 2019 iMac desktop, to mute the power on chime I simply boot up in MacOS, turn the sound down to 0 (mute) and then power down.

From that point forward, the Linux power up routine does not play any chime.

(Of course, one would need some vestige of the MacOS boot up capability - i.e., dual boot - in order to use this method.)

:vulcan_salute:

3

In my case there is no duel boot option. I tried many options in Apple Recovery terminal (but only this worked).

4

Did some testing on a Macbook Air A1466 and noticed the following solution possibly because Apple security defaults are different after you install via USB. One symptom is it would not let you boot from USB unless you reset all the nvram settings.

In some cases the value “SystemAudioVolume-7c436110-ab2a-4bbb-a880-fe41995c9f82” will not be listed as a variable to be updated. Then the only way to update the boot volume is to use MacOS Recovery mode:

  1. Turn on computer.

  2. Hold down <Command + R> to enter Macbook Recovery mode.

  3. Open Terminal from the Utility menu.

  4. Run the command “nvram SystemAudioVolume=%01” to change the volume to the minimum settings.

  5. Restart the Mac computer.

Note:

  • The following are not available in Macbook Recovery mode:

    • The System Integrity Protection (SIP) command .

    • sudo to elevate rights.

  • The command "nvram SystemAudioVolume=%00" did not work to reduce volume