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' is the disk number, 'y' the partition number. "Hide Partition" Remove unwanted partition(s) from the boot menu. =hd(x,y) [hd(m,n)] arch= Force ABI to 32/64 bit and load 32/64 bit kernel. -x32 Enable forcing 32 bit ABI only and load 32 bit kernel. -x64 Enable forcing 64 bit ABI and load 64 bit kernel. LoadTestDrivers=Yes|No Enable loading of test drivers from /Test/Extensions(.mkext) 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 graphics cards. VideoROM= Use an alternate ROM image (default path: /NVIDIA.ROM). VBIOS=Yes|No Inject VBIOS to device-properties. EthernetBuiltIn=Yes|No Automatic "built-in"=yes device-properties generation for ethernet interfaces. UpdateACPIVersion=Yes Enable ACPI V1 to ACPI V4 upgrade (disabled by default). FixRestart=Yes Enable the restart fix (disabled by default). ForceHPET=Yes Force HPET on (disabled by default). USBBusFix=Yes Enable the EHCI and UHCI fixes (disabled by default). EHCIacquire=Yes Enable the EHCI fix (disabled by default). UHCIreset=Yes Enable the UHCI fix (disabled by default). USBLegacyOff=Yes Force USB Legacy off (disabled by default). Wake=No Disable wake up after hibernation (enbaled by default). ForceWake=Yes Force using the sleepimage (disabled by default). WakeImage= Use an alternate sleepimage file (default path is /private/var/vm/sleepimage). PMProfile=<0-7> Set preferred power management profile. oemDSDT=Yes Use standard DSDT and don't patch ACPI. oemHPET=Yes Use standard HPET table. oemSSDT=Yes Use standard SSDT tables. oemHPET=Yes Use standard HPET table. oemSBST=Yes Use standard SBST table. oemECDT=Yes Use standard ECDT table. oemASFT=Yes Use standard ASF! table. oemDMAR=Yes Use standard DMAR table. oemFADT=Yes Use standard FADT table. oemAPIC=Yes Use standard APIC table. oemMCFG=Yes Use standard MCFG table. DropSSDT=Yes Skip the SSDT tables while relocating the ACPI tables. DropHPET=Yes Skip the HPET table while relocating the ACPI tables. DropSLIC=Yes Skip the SLIC table while relocating the ACPI tables. DropSBST=Yes Skip the SBST table while relocating the ACPI tables. DropECDT=Yes Skip the ECDT table while relocating the ACPI tables. DropASFT=Yes Skip the ASF! table while relocating the ACPI tables. DropDMAR=Yes Skip the DMAR table while relocating the ACPI tables. DSDT= Use an alternate DSDT.aml file (default path: /DSDT.aml /Extra/DSDT.aml) HPET= Use an alternate HPET.aml file (default path: /HPET.aml /Extra/HPET.aml) SBST= Use an alternate SBST.aml file (default path: /DSDT.aml /Extra/SBST.aml) ECDT= Use an alternate ECDT.aml file (default path: /ECDT.aml /Extra/ECDT.aml) DSDT= Use an alternate DSDT.aml file (default path: /DSDT.aml /Extra/DSDT.aml) ASFT= Use an alternate ASFT.aml file (default path: /ASFT.aml /Extra/ASFT.aml) DMAR= Use an alternate DMAR.aml file (default path: /DMAR.aml /Extra/DMAR.aml) FADT= Use an alternate FADT.aml file (default path: /FADT.aml /Extra/FADT.aml) APIC= Use an alternate APIC.aml file (default path: /APIC.aml /Extra/APIC.aml) MCFG= Use an alternate MCFG.aml file (default path: /MCFG.aml /Extra/MCFG.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 issues 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.