Apple's Move to Intel

• For years, Apple used PowerPC chips in its computers and the PowerBook laptop line. When the company decided to move to the Intel platform of chips, the Open Firmware solution used previously was no longer compatible. The company used the switch as an opportunity to bring its BIOS up to date and implement the EFI system on its laptop line. Without a PowerPC chip, the PowerBook was changed to the Macbook and it shipped with EFI.
  
  

MacBook EFI and Windows

• With the implementation of EFI technology, Apple used this to lock down the OSX operating system to its shipped hardware so it could not be ran on any machine other than one Apple manufactured. To counter possible hacking of the operating system to other machines, Apple set its EFI to allow Windows to run native on the MacBook hardware via Boot Camp. Early reports showed that Windows running on a Mac were faster than any Windows machines on the market.
  
  

Moving to 64-Bit

• The version of EFI used on MacBook's were version 1.10 and limited the operating system to 32-bit operations, while the Intel chips shipping were capable of 64-bit operations. Later in 2006, Apple adjusted the EFI software to "Fat EFI," allowing the operating system to use either 32- or 64-bit modes. This code was written by Apple and brought its EFI implementation into a non-compatible state from older versions.
  
  

Hacking EFI Protections

• With EFI rollouts on the MacBook, people have worked to circumvent its protections. Protections include firmware passwords and disallowing booting of the operating system until proper access is granted. If no password is set for the EFI protections, people have found that the default password can be easily guessed.
  
  Methods for getting around the EFI protections have ranged from constant tries (also known as brute force) and running automated scripts to fake data the Mac looks for. By working around the locks of the hardware, people are able to customize the software to run on any machine they want and also modify its settings to perform functions not intended by Apple.
  
  

High-Profile EFI Hacks

• Some hacks of the EFI system have made headlines in the tech-circles when in 2008 a company called Psystar used hacked EFI software to sell Apple's OSX on its own hardware. This was the first time EFI was used to circumvent Apple's tight controls on its products. Apple secured an injunction against Psystar in December of 2009, but the legal paperwork did not mention Psystar's use of hacked EFI firmware as being illegal. The use of EFI on MacBook computers continues to lock the software to the machine in the way that only Apple intends. In January of 2010, Psystar announced it was appealing the legal rulings against it so its hacked EFI could once again be used.