Boot Codes

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All versions of Linux allow you to add various boot codes (sometimes also called cheat codes or kernel boot options). These codes alter the operation of the OS in many varied but very specific ways.

Many users have found advantages in altering syslinux.cfg with boot codes to accommodate unusual hardware problems.

The syslinux.cfg file may look like the following (make sure you start from the current cfg file you have in place. This is for example only)

default menu.c32
menu title Lime Technology LLC
prompt 0
timeout 50
label unRAID OS
  menu default
  kernel bzimage
  append initrd=bzroot
label Memtest86+
  kernel memtest

You can add several extra options to the append line such as:

append initrd=bzroot acpi=off nolapic noapic vga=extended


A few of the more common additions are as follows

  • nolapic
    • may be required to get some motherboards to work
  • noapic
    • may be required to get some motherboards to work
    • may be required for boards based on the nForce 5 or higher chipsets, until unRAID v4.4 final
  • acpi=off
    • may be required to get some motherboards to work
  • acpi=force
    • may be required to get some motherboards to work (Asus P4SDX may need this)
  • irqpoll
    • wastes cpu cycles, but is sometimes needed for some motherboards
  • pci=routeirq
    • may be required to get some motherboards to work
  • pci=noacpi
    • may be required to get some motherboards to work
  • pci=nomsi
    • may be required to get some motherboards to work
  • swncq=0
    • only if needed, for boards based on the nForce 5 or higher chipsets, and possibly only for unRAID v4.4-beta2
  • vga=extended or vga=6

More boot parameters can be found here, but use with care. Additional help with ACPI boot options is here. A more complete reference is here.

Note: apart from the vga parameter, do not add more parameters than are absolutely necessary to get your system to boot. For example, if you find that acpi=off nolapic noapic helps your system to boot, try eliminating one or more of these, to the absolute minimum required. Adding any variation of the vga parameter does not matter, but the rest of these are only workarounds, not desirable additions, and you only want to add one if it is required for successful operation.


Note on editing 'syslinux.cfg' in Windows: use Microsoft WordPad or an editor that can be configured to use Unix end-of-line's. Do not use Notepad, Microsoft Word, or any editor that you can not adjust the end-of-line character. In WordPad, when finished, use the Save command, or the Save As Text Document, not Save As MS-DOS Format.