Chameleon is the open source bootloader derived from the boot-132 developed by David Elliott which came from Apple and was the final release of their bootcode which was originally developed for the Darwin project. Apple Macs have an EFI based system for booting OS X on an x86 system so when Darwin was still being maintained a bootloader was needed for BIOS based systems which could pass things like the device tree to the kernel. For more information on this see David Elliott's site here.

Until mid 2008 the best available bootloader was a modified boot-132 from netkas and others which provided rudimentary EFI emulation allowing the OS X system to 'see' the system as real and make use of an unmodified hardware on a compatible CPU. In June of 2008 David Elliott released an updated boot-132 source which allowed additional kexts (kernel extensions) to be loaded from a ramdisk based on the syslinux software available. This allowed hardware drivers to be loaded externally from an unmodified system effectively allowing the use of an unmodified DVD or install to be loaded, again if compatible hardware is present.

It is here the Chameleon project was born. An open source bootloader fork based upon Boot-132 designed to boot Mac OS X on generic x86 based systems with additional features added as time progressed.

Components

The essential components of Chameleon are just 3 files, boot0 which is written to the MBR and is compatible with both MBR and MBR/GPT configured partition tables. boot1h which is then loaded by boot0 and is written to the bootsector of a partition. As of Chameleon 2.0 this can be the EFI partition and works on both FAT32 and HFS+ formatted partitions. Finally the file boot is loaded from the root of the bootsector with boot1h installed. This is where most of the code resides including loading additional kexts and the themed GUI. One of the limitations of Chameleon 1.x was that boot could only be a maximum size of 64kb however this has been overcome in 2.0. For more information see the wikipedia article on MBR.

Features and Configuration

EFI Emulation

• Perhaps the most important feature of Chameleon is it's ability to emulate an EFI system on a traditional BIOS only system. This includes generating an EFI system table which can then be passed to IOKit. David Elliott details this well on his boot-132 page.

Extra Extensions Loading

DSDT Override

• Originally developed by mackerintel this feature allows the DSDT table contained in the BIOS of every system to be overriden and replaced with a modified one designed to fix many problems encountered in OS X due to a badly or incompatibly configured DSDT table in the BIOS.
• Chameleon will look to load a DSDT.aml file from /DSDT.aml or /Extra/DSDT.aml. Additionally Chameleon can be passed the DSDT flag to specify a different DSDT. On the command line it will look as such: "DSDT"="/Extra/randomdsdt.aml" This can also be specified in the com.apple.Boot.plist

com.apple.Boot.plist Loading

• Chameleon will look in the default location of /Library/Preferences/SystemConfiguration/com.apple.Boot.plist but will override the default with one located in /Extra/com.apple.Boot.plist if found. This avoids editing the default system plist.

SMBIOS Patching

This is just an article to collect together all the available resources for running Mac OS X on a Dell XPS M1530 laptop. I will include guides, documentation and any needed files in attempt to make things easier for those with this laptop.

Guides

Installing Leopard on an XPS M1330/M1530 Tutorial by wingrunr21

This is a very comprehensive guide that covers various methods of installing including retail and goes into detail how to get all your hardware working. This is the best starting place I can recommend. If you are looking to do a Snow Leopard install there are also many details on that in this thread.

Link: http://www.insanelymac.com/forum/index.php?showtopic=119654

DSDT Modification guide for the XPS M1330/M1530 by immo

A fantastic guide for those who wish to have as close to a retail install as possible by fixing things via DSDT. immo covers everything from enabling the nVidia graphics card to fixing that annoying IDE problem in Snow Leopard.

Link: http://www.insanelymac.com/forum/index.php?showtopic=190780

AppleHDA Solutions Thread by talisman

This contains the most up to date patched AppleHDA kexts for enabling sound for users with the SigmaTel 9228 found in the M1530 and M1330. With it you should be able to get internal speakers, outputs and microphones working so keep an eye on this for the latest fixes.

Link: http://www.insanelymac.com/forum/index.php?showtopic=142521

Common Problems and Solutions

nVidia Graphics are low resolution or do not have QE/CI

To fix this you need to enable the built in graphics kexts. You can do this in 4 different ways depending on what suits your needs.

Ethernet doesn't work or has the wrong MAC address

As of OS X Leopard 10.5.6 and Snow Leopard 10.6 ethernet is supported by the AppleYukon2.kext natively without modification. The kext can't however read the ROM of 88E8040 and will return a MAC address of 00:11:22:33:44:55. If necessary this can be fixed by hex editing the kext binary to replace it with your own. This will need to be done for each system update where the kext is updated however. See this thread for the latest on how to patch your MAC.

IOATAFamily.kext is causing a kernel panic on my system or my DVD drive doesn't work

The built in Snow Leopard IOATAFamily.kext can cause problems with Intel chipset based laptops that utilise IDE channels for the DVD drive due to the secondary IDE channel being disabled. The solution to get past the kernel panic is to remove the kext or apply a DSDT patch. To re-enable your DVD drive later you can replace the stock IOATAFamily.kext with a patched one or again utilise a DSDT patch.

The patched IOATAFamily can be found here and the guide for the DSDT fix can be found in the guide I posted earlier or in this thread.

WiFi doesn't work!

This is because the Intel WiFi cards are currently unsupported under OS X. However there may in the future be support thanks to a personal project undertaken by mercurysquad. Currently the 3945 is supported and the 4965 support is in the works. To follow this project see this blog.

Card Reader doesn't function

This can be enabled for SD/SDHC and MMC reading by installing VoodooSDHC for Snow Leopard, see here, or for Leopard by using the older IOSDHCIBlockDevice kext found here.

Fingerprint scanner support

Upek fingerprint scanners are supported under OS X and official drivers can be found on their site. See the download page for both Leopard and Snow Leopard support.