Disable Boot Chime on Late 2009 MacBook Without macOS

bootmacbook pro

I would like to disable the boot/power-on chime on a late 2009 MacBook. However, my system does not have macOS installed at all. Is there a way to do this without reinstalling macOS?

The machine has Linux installed, though it often runs FreeBSD as well.

Best Answer

The Start up chime resides in the NVRAM.

To disable it in OS X run sudo nvram BootAudio=%00

I found this for Linux:

# efivar -l | grep SystemAudioVolume
 7c436110-ab2a-4bbb-a880-fe41995c9f82-SystemAudioVolume
 7c436110-ab2a-4bbb-a880-fe41995c9f82-SystemAudioVolumeDB

# efivar -n 7c436110-ab2a-4bbb-a880-fe41995c9f82-SystemAudioVolume -p
GUID: 7c436110-ab2a-4bbb-a880-fe41995c9f82
Name: "SystemAudioVolume"
Attributes:
    Non-Volatile
    Boot Service Access
    Runtime Service Access
Value:
00000000  00                                                |.               |

# efivar -n 7c436110-ab2a-4bbb-a880-fe41995c9f82-SystemAudioVolumeDB -p
GUID: 7c436110-ab2a-4bbb-a880-fe41995c9f82
Name: "SystemAudioVolumeDB"
Attributes:
    Non-Volatile
    Boot Service Access
    Runtime Service Access
Value:
00000000  00 
#

SOURCE

Related Question