SW:NVRAM

Types

• string: A standard string.
• bin-string: A URL-encoded string containing binary data.
• bool: A string with value of either true or false.
• int: A decimal integer.
• bin-int(n): A bin-string-encoded integer, little-endian, n bytes.
• hex-int: A hexadecimal integer.
• plist: A bin-string encoded binary property list.
• volume: A string of format <gpt-partition-type-uuid>:<gpt-partition-uuid>:<volume-group-uuid>. The GPT partition UUID seems to be a bit weird, with its first three components byteswapped.

Values

Boot

• auto-boot: {true,false}: Whether to automatically boot. Setting this to false on at least the Mac M1 mini causes a boot failure;
• boot-args: string: Boot arguments to pass to the kernel. Possibly filtered by the boot policy.
• boot-info-payload: bin-string: Some kind of opaque, high-entropy payload.
• boot-note: bin-string: Unknown. Example: %00%00%00%00%00%00%00%bb%0ez%e5%00%00%00%00%a0q%d4%07%08%00%00%00
• boot-volume: volume: Default boot volume.
• update-volume: volume
• upgrade-boot-volume: volume

Firmware

• ota-controllerVersion: string: Over-the-air update controller identifier. Examples: SUMacController-1.10 (Mac Mini M1), SUS-1.0 (iPhone, iPad).
• ota-updateType: string: Type of over-the-air updates to apply. Example: incremental.
• usbcfwflasherResult: string: Example: No errors.

Settings

• backlight-nits: hex-int: Presumably the screen backlight strength. Mac Mini M1 example: 0x008c0000.
• current-network: bin-string: Last Wi-Fi networks to have connected to.
• fmm-computer-name: string: Computer name.
• good-samaritan-message: string: Message to show on the boot/password screen in case the device is lost and found.
• preferred-networks: bin-string: List of stored Wi-Fi networks.
• preferred-count: int: Number of networks in preferred-networks, if not 1.
• prev-lang:kbd: string: Keyboard layout, format: <lang>:<locale-id>, reference. Example: en-GB:26.
• prev-lang-diags:kbd: string: Keyboard layout in diagnostics: Example: en-GB.
• SystemAudioVolume: bin-int(8): Volume. Example: %80 (128).
• SystemAudioVolumeExtension: bin-int(16): Example: %ff%7f (32767).