Boot Mac Os X

The BootX booting screen used on Macintoshes with Mac OS X 10.2 or later
Developer(s)Apple Inc.
Initial releaseAugust 24, 2002 (with Mac OS X 10.2)[1][2]
Operating systemDarwin & Mac OS X[3]
TypeBoot loader
LicenseApple Public Source License[5]

For the similarly-named bootloader that is one of the bootloaders that enables Old World PowerPC Macintoshes to boot native (i.e. non-MkLinux) Linux, please see BootX (Linux).

N: Start up from a NetBoot server, if your Mac supports network startup volumes. To use the default boot image on the server, press and hold Option-N instead. Disabled when using a firmware password. Command-S: Start up in single-user mode. Disabled in macOS Mojave or later, or when using a firmware password. T: Start up in target disk mode. Here’s how to install macOS from an OS X boot USB drive: 1. Connect the carrier to the Mac you want to install the OS on. Open the installation manager. Select the internal disk of the Mac as the boot volume and click Continue. Restart the Mac from this disk.

BootX is a software-based bootloader designed and developed by Apple Inc. for use on the company's Macintosh computer range. BootX is used to prepare the computer for use, by loading all required device drivers and then starting-up Mac OS X by booting the kernel on all PowerPC Macintoshes running the Mac OS X 10.2 operating system or later versions.[2][6]

Using BootROM, a read-only memory (ROM) computer chip containing OpenFirmware, a graphical bootsplash is shown briefly on all compatible Macintosh computers as a grey Apple logo with a spinning cursor that appears during the startup sequence.[7]

The program is freely available as part of the Darwinoperating system under the open-sourceApple Public Source License.[5]

BootX was superseded by another nearly identical bootloader named boot.efi and an Extensible Firmware InterfaceROM on the release of the Intel-based Mac.[4]


Old World boot icon
New World boot icon

Older Macintoshes dating from 1983 until 1998 utilized a basic bootloader; the bootloader was solely a ROM chip varying in sizes up to 4 megabytes (MB), which contained both the computer code to boot the computer and to run the Mac OS operating system.[8] The ROM-resident portion of the Mac OS is the Macintosh Toolbox and the boot-ROM part of that ROM was retroactively named Old World ROM upon the release of the New World ROM Macs, starting with the first iMac. The ROM-resident Macintosh Toolbox differs greatly from the design of the modern Macintosh, which generally use a hard drive of large capacity to store the operating system. This bootloader was used in all Macintosh computers until mid-1998.[9]

With the advent of the iMac series of Macintoshes, the firmware was updated.[10] The ROM was reduced in size to 1 MB, called BootROM, and the remainder of the ROM was moved to the file Mac OS ROM in the Mac OS System Folder, stored on the hard drive.[9] This ROM used a full implementation of the OpenFirmware standard (contained in BootROM) and was named the New World ROM.[11]

In 2001, with the release of Mac OS X 10.0, the Mac OS ROM file was replaced with the BootX bootloader file.[9] In 2002, with the release of Mac OS X 10.2, the historical 'Happy Mac' start-up picture was replaced with a grey apple logo.[12] By introducing the Intel Mac in 2006, BootROM was replaced by the near identical Extensible Firmware Interface ROM (although Apple still calls it BootROM) and the boot.efi file.[4][13]


To make the boot loader appealing to other operating system developers, Apple added features to allow flexibility in the booting process such as network boot using TFTP and load Mach-O and ELF formatted kernels. BootX can also boot from HFS, HFS+, UFS and ext2formatted volumes.[14] The boot loader can be manipulated at startup by holding down various key combinations to alter the booting process. Such functions include Verbose Mode, achieved by holding down the Command and V key at startup, which replaces the default Apple logo with text-based information on the boot process and Single User Mode, achieved by holding down the Command and S, which, depending on the operating system, may boot into a more basic command-line or text-based version of the operating system, to facilitate maintenance and recovery action.[15] The ROM can also be set to require a password to access these technical functions using the OpenFirmware interface.[16]


Boot process[edit]

Mac OS X booting up in single-user mode

In PowerPC-based Macintoshes, the boot process starts with the activation of BootROM, the basic Macintosh ROM, which performs a Power On Self Test to test hardware essential to startup.[4] On the passing of this test, the startup chime is played and control of the computer is passed to OpenFirmware. OpenFirmware initializes the Random Access Memory, Memory Management Unit and hardware necessary for the ROM's operation. The OpenFirmware then checks settings, stored in NVRAM, and builds a list of all devices on a device tree by gathering their stored FCode information.[6]

On the completion of this task, BootX takes over the startup process configuring the keyboard and display, claiming and reserving memory for various purposes and checking to see if various key combinations are being pressed.[7] After this process has been completed BootX displays the grey Apple logo, spins the spinning wait cursor, and proceeds to load the kernel and some kernel extensions and start the kernel.[17]


  1. ^'Jaguar 'Unleashed' at 10:20 p.m. Tonight'. Apple Inc. August 23, 2002. Retrieved June 12, 2019.
  2. ^ abSiracusa, John (September 5, 2002). 'Mac OS X 10.2 Jaguar'. Ars Technica. p. 3. Retrieved January 26, 2016.
  3. ^'Darwin 9.2 Source Code'. Apple Inc. Retrieved June 12, 2019.
  4. ^ abcd'System Startup Programming Topics: The Boot Process'. Apple Inc. February 8, 2007. Archived from the original on July 6, 2008. Retrieved May 1, 2008.
  5. ^ ab'Apple Public Source License'. Apple Inc. August 6, 2003. Retrieved July 23, 2017.
  6. ^ abSingh, Amit (2007) [2006]. 'The Firmware and the Bootloader'. Mac OS X Internals: A Systems Approach. Addison-Wesley. pp. 324–325. ISBN978-0-321-27854-8. Retrieved May 3, 2008.
  7. ^ abTanous, Jim. 'Booting Mac OS X'. tekrevue.com. Retrieved September 29, 2014.
  8. ^'Macintosh: ROM Size for Various Models'. Apple Inc. August 23, 2000. Archived from the original on June 21, 2002. Retrieved May 15, 2008.
  9. ^ abcSingh, Amit (2007) [2006]. 'The Firmware and the Bootloader'. Mac OS X Internals: A Systems Approach. Addison-Wesley. pp. 267–268. ISBN978-0-321-27854-8. Retrieved May 3, 2008.
  10. ^'Apple Announces Mac OS 9: The Best Internet OS Ever'. Apple Inc. October 5, 1999. Archived from the original on December 17, 2008. Retrieved May 17, 2008.
  11. ^'The Macintosh ROM and The NewWorld Architecture'. Apple Inc. March 26, 1999. Archived from the original on September 24, 2004. Retrieved May 15, 2008.
  12. ^Markoff, John (August 26, 2002). 'Compressed Data; Happy Mac Becomes an Icon of the Past'. The New York Times. New York. Retrieved May 17, 2008.
  13. ^'Apple Unveils New iMac with Intel Core Duo Processor' (Press release). Apple Inc. January 10, 2006. Retrieved October 20, 2019.
  14. ^Gerbarg, Louis. 'BootX: The Mac OS X Bootloader'(PDF). Rensselaer Polytechnic Institute - Computer Science Department. pp. 7–8. Archived from the original(PDF) on March 9, 2007. Retrieved May 1, 2008.
  15. ^'Mac OS X keyboard shortcuts'. Apple Inc. October 17, 2007. Archived from the original on April 23, 2008. Retrieved May 2, 2008.
  16. ^'Setting up firmware password protection in Mac OS X'. Apple Inc. Retrieved May 3, 2008.
  17. ^Tanous, Jim. 'Mac OS X System Startup'. tekrevue.com. Retrieved September 29, 2014.

External links[edit]

  • Mac OS X at osxbook.com
Retrieved from 'https://en.wikipedia.org/w/index.php?title=BootX_(Apple)&oldid=1034399007'

Have you ever been faced with the need to install a new operating system on a crashed PC but realize that you don't have the installation disc? For most people, such a case is always discouraging and disheartening because they know that the only way to install a new OS is to use an installation disc. Actually, all you need is a USB with a good capacity and a utility like Rufus. Rufus is a free, portable open-source utility that you can use to create bootable USB flash drives. Rufus is small in size, but it surprisingly has everything you need as far as the above are concerned.

Does Rufus Have a Mac Version?

Rufus is primarily a Windows application and currently, it supports 64 or 32 bit Windows XP/7/8/10 only. This means that you can not use Rufus on the normal Mac computers. If you need to run Rufus on a Mac, then it will be imperative for the computer to have a dual boot Windows installed on Mac. However, this is not an easy task at all.

To those in the dark, this simply means that you will need to have a Windows Operating system installed in your Mac computer. However, if you didn't want to have two operating systems running on the same machine so that you can access Rufus, there are quite a number of alternatives you can use to achieve the same functionalities of Rufus on Mac.

Rufus for Mac Alternative 1: UUByte ISO Editor

UUByte ISO Editor is by far one of the best ISO toolkits for those who want a seamless process in creating, burning, extracting and editing ISO images. Unlike Rufus, it has both Windows and Mac versions so you don't have to worry about not having Rufus for Mac or the need to install two operating systems in your Mac.

This ISO editor can effortlessly burn ISO image to DVD, CD or USB which you can then go ahead and use as a bootable disc for new installation. The tool is also versatile enough to create an ISO archive from folders or external sources, in addition to extracting or mounting ISO files to Mac or Windows computers. With over 220,000 users worldwide, it is a clear winner among the ISO toolkits available in the market today.

Why Choose UUByte ISO Editor

  • Full ISO toolkit for Windows and Mac.
  • Easily create bootable USB or DVD from Windows ISO.
  • 5X faster burning speed.
  • Excellent customer support.

How to burn ISO to USB on Mac using UUByte ISO Editor: Please download UUByte ISO Editor for Mac and install the app. Then drag and drop the app icon to Application folder so you can open the app from Launchpad. After that, insert a USB stick and click 'Burn' button at the first screen. Now import Windows ISO to the program and start burning ISO to USB by clicking 'Burn' button at the bottom of the Window. Finally, wait for 10 minutes to get the job done.

Rufus for Mac Alternative 2: UNetbootin

Unetbootin (Universal Netboot Installer) , is another cross-platform utility toolkit that makes a great alternative to Rufus on Mac. It has the ability to load and install various Linux distros on Mac. It is easy to use and supports a myriad of platforms. All you have to do is select an ISO file or the specific distribution you want to download and then simply choose the target drive. It also comes with a nice GUI, which further adds to the user experience during use.

Mac Os X Download


  • Support Windows, Mac and Linux.
  • Able to download Linux ISO within the program.
  • Easily create ISO image from files or folders.


  • Non-native user interface.
  • Lower success rate on new USB drives.
  • Lack support for CD or DVD.

Rufus for Mac Alternative 3: Etcher

Etcher is another great Rufus alternative for Mac. It has been designed to allow you to easily and comfortably burn ISO images to USB drives and SD cards. The utility comes with an advanced interface which may be intimidating on first glance, but after going through the simple user guide, getting around to use the utility becomes a breeze.

Simply download this tool, launch it, and then choose the IMG file you are interested in burning. You will then select the location of the target USB drive or SD card and then wait for it to do its magic. It is lightweight and relatively fast, so you won't have to wait for a whole day for the burning process to end.

Mac Os X Update


  • Polish user interface.
  • Support USB drives as well as SD cards.
  • Easy to use.


  • Being loaded slowly on startup.
  • Get stuck at burning process easily.
  • Poor support for Windows 10 ISO.


Safe Boot Mac Os X

Rufus is a great application for burning ISO to USB. Unfortunately, there is no Mac version yet. So for burning ISO to USB on Mac, you have to use third-party alternatives like UUByte ISO Editor to get it done. The suggestions in this post almost do the same thing as Rufus on Windows so don't worry about the functionality. Go ahead and pick up the best rufus alternative according to your experience.

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