Note: before you do anything with clearing nvram, keep in mind that doing so clears any kext whitelisting you may have done previously!
macOS has the ability to delete all of the firmware variables you’ve created. This can get helpful if you’ve got a bunch of things that you’ve done to a system and want to remove them all. If you run nvram followed by a -p option you’ll see all of the configured firmware variables:
nvram -p
The output would be as follows:
efi-boot-device-data %02%01%0c%00%d0A%03%0a%00%00%00%00%01%01%06%00%05%1c%01%01%06%00%00%00%03%12%0a%00%00%00%00%00%00%00%04%01*%00%02%00%00%00(@%06%00%00%00%00%00X%a8#:%00%00%00%00%eee6%da%00%0b%09G%82%c9%bd4wpQ%82%02%02%04%03$%00%f7%fct%be|%0b%f3I%91G%01%f4%04.hBw;%1a$%82%a3>D%92#%80%e9o%a9!%de%04%04%9a%00\%00A%003%000%006%00A%004%00F%00D%00-%00F%00F%00B%005%00-%003%00F%00A%002%00-%008%00D%00C%004%00-%00B%00F%007%003%00E%007%00F%003%008%00C%007%00E%00\%00S%00y%00s%00t%00e%00m%00\%00L%00i%00b%00r%00a%00r%00y%00\%00C%00o%00r%00e%00S%00e%00r%00v%00i%00c%00e%00s%00\%00b%00o%00o%00t%00.%00e%00f%00i%00%00%00%7f%ff%04%00
efi-boot-device <array><dict><key>IOMatch</key><dict><key>IOProviderClass</key><string>IOMedia</string><key>IOPropertyMatch</key><dict><key>UUID</key><string>241A3B77-A382-443E-9223-80E96FA921DE</string></dict></dict><key>BLLastBSDName</key><string>disk1s2</string></dict><dict><key>IOEFIDevicePathType</key><string>MediaFilePath</string><key>Path</key><string>\A306A4FD-FFB5-3FA2-8DC4-BF73E7F38C7E\System\Library\CoreServices\boot.efi</string></dict></array>%00BootCampProcessorPstates %0c%00 bluetoothInternalControllerInfo %90%82%ac%05%00%000%14%f4\%89%adF%f prev-lang:kbd en:0 SystemAudioVolumeDB %e4
efi-apple-recovery <array><dict><key>IOMatch</key><dict><key>IOProviderClass</key><string>IOMedia</string><key>IOPropertyMatch</key><dict><key>UUID</key><string>3D351489-745F-4434-89E0-DC914B49969F</string></dict></dict><key>BLLastBSDName</key><string>disk0s1</string></dict><dict><key>IOEFIDevicePathType</key><string>MediaFilePath</string><key>Path</key><string>\EFI\APPLE\FIRMWARE\MBP121_0171_B00.fd</string></dict></array>%00
previous-system-uuid A306A4FD-FFB5-3FA2-8DC4-BF73E7F38C7E
bluetoothActiveControllerInfo %90%82%ac%05%00%00%00%000%14%f4\%89%adF%fa
ALS_Data ^%0d%8a%8a%00%00%00%00
backlight-level %10%02
SystemAudioVolume G
LocationServicesEnabled %01
If you run it with a -d you’ll delete the given variables that you define (e.g. boot-args):
nvram -d boot-args
But, if you run the -c you’ll wipe them all:
nvram -c
