i386/strings/BootHelp.txt

   1 The boot: prompt waits for you to type advanced startup options.
   2 If you don't type anything, the computer continues starting up normally. It
   3 uses the kernel and configuration files on the startup device, which it also
   4 uses as the root device. Advanced startup options use the following syntax:
   5     [device]<kernel> [arguments]
   6 Example arguments include
   7  device: rd=<BSD device name>       (e.g. rd=disk0s2)
   8          rd=*<IODeviceTree path>    (e.g. rd=*/PCI0@0/CHN0@0/@0:1)
   9  kernel: kernel name                (e.g. "mach_kernel" - must be in "/" )
  10  flags: -v (verbose)    -s (single user mode),
  11         -x (safe mode)  -F (ignore boot configuration file)
  12  "Graphics Mode"="WIDTHxHEIGHTxDEPTH" (e.g. "1024x768x32")
  13     For VESA 3.0 graphics, you may append a refresh rate
  14     after an "@" character (e.g. "1280x1024x32@75")
  15  kernel flags                       (e.g. debug=0x144)
  16  io=0xffffffff                      (defined in IOKit/IOKitDebug.h)
  17
  18 Example: mach_kernel rd=disk0s1 -v "Graphics Mode"="4096x4096x32@85"
  19
  20 If the computer won't start up properly, you may be able to start it up using
  21 safe mode.  Type -x to start up in safe mode, which ignores all cached
  22 driver files.
  23
  24 Special booter commands:
  25   ?memory    Displays information about the computer's memory.
  26   ?video     Displays VESA video modes supported by the computer's BIOS.
  27
  28 Additional useful command-line options:
  29   config=<file>             Use an alternate Boot.plist file.
  30   platform=ACPI|X86PC       Use either ACPI or non-ACPI platform support.
  31
  32 Options useful in the com.apple.Boot.plist file:
  33   "Boot Graphics"=Yes|No    Use graphics mode or text mode when starting.
  34   "Quiet Boot"=Yes|No       Use quiet boot mode (no messages or prompt).
  35   Timeout=8                 Number of seconds to pause at the boot: prompt.