The boot: prompt waits for you to type advanced startup options. If you don't type anything, the computer continues starting up normally. It uses the kernel and configuration files on the startup device, which it also uses as the root device. Advanced startup options use the following syntax: [device] [arguments] Example arguments include device: rd= (e.g. rd=disk0s2) rd=* (e.g. rd=*/PCI0@0/CHN0@0/@0:1) kernel: kernel name (e.g. "mach_kernel" - must be in "/" ) flags: -v (verbose) -s (single user mode), -x (safe mode) -F (ignore boot configuration file) "Graphics Mode"="WIDTHxHEIGHTxDEPTH" (e.g. "1024x768x32") kernel flags (e.g. debug=0x144) io=0xffffffff (defined in IOKit/IOKitDebug.h) Example: mach_kernel rd=disk0s1 -v "Graphics Mode"="1920x1200x32" If the computer won't start up properly, you may be able to start it up using safe mode. Type -x to start up in safe mode, which ignores all cached driver files. Special booter hotkeys: F5 Rescans optical drive. F10 Scans and displays all BIOS accessible drives. Special booter commands: ?memory Displays information about the computer's memory. ?video Displays VESA video modes supported by the computer's BIOS. ?norescan Leaves optical drive rescan mode. Additional useful command-line options: config= Use an alternate Boot.plist file. Options useful in the com.apple.Boot.plist file: Wait=Yes|No Prompt for a key press before starting the kernel. Quiet Boot=Yes|No Use quiet boot mode (no messages or prompt). Timeout=8 Number of seconds to pause at the boot: prompt. Instant Menu=Yes Force displaying the partition selection menu. Default Partition Sets the default boot partition, =hd(x,y)| where 'x' & 'y' are the disk and partition numbers = or specify the selected volume UUID string. Hide Partition Remove unwanted partition(s) from the boot menu. =hd(x,y) [hd(m,n)] only non mac osx boot partitions can be hidden. Rename Partition Rename partition(s) for the boot menu. =hd(x,y) [;hd(m,n) ...] GUI=No Disable the GUI (enabled by default). Boot Banner=Yes|No Show boot banner in GUI mode (enabled by default). Legacy Logo=Yes|No Use the legacy grey apple logo (disabled by default). PciRoot= Use an alternate value for PciRoot (default value 0). GraphicsEnabler=Yes|No Automatic device-properties generation for gfx cards. UseAtiROM=Yes|No Use an alternate Ati ROM image (path: /Extra/_.rom) UseNvidiaROM=Yes|No Use an alternate Nvidia ROM image (path: /Extra/_.rom) VBIOS=Yes|No Inject VBIOS to device-properties. EthernetBuiltIn=Yes|No Automatic "built-in"=yes device-properties generation for ethernet interfaces. USBBusFix=Yes Enable all USB fixes below: EHCIacquire=Yes Enable the EHCI fix (disabled by default). UHCIreset=Yes Enable the UHCI fix (disabled by default). USBLegacyOff=Yes Enable the USB Legacy fix (disabled by default). ForceHPET=Yes|No Force Enable HPET. Wake=No Disable wake up after hibernation (default: enabled). ForceWake=Yes Force using the sleepimage (disabled by default). WakeImage= Use an alternate sleepimage file. (default path is /private/var/vm/sleepimage). DropSSDT=Yes Skip the SSDT tables while relocating the ACPI tables. DSDT= Use an alternate DSDT.aml file (default path: /DSDT.aml /Extra/DSDT.aml). SMBIOS= Use an alternate smbios.plist file (default path: /smbios.plist /Extra/smbios.plist bt(0,0)/Extra/smbios.plist). SMBIOSdefaults=No Don't use the Default values for SMBIOS overriding if smbios.plist doesn't exist, factory values are kept. Scan Single Drive Scan the drive only where the booter got loaded from. =Yes|No Fix rescan pbs when using a DVD reader in AHCI mode. Rescan=Yes Enable CD-ROM rescan mode. Rescan Prompt=Yes Prompts for enable CD-ROM rescan mode. SystemId= Set manually the system id UUID, SMUUID in smbios config (reserved field) isn't used. SystemType= Set the system type where n is between 0..6 (default =1 (Desktop) md0= Load raw img file into memory for use as XNU's md0 ramdisk. /Extra/Postboot.img is used otherwise.