Mac Classic

Most of the Apple G4 models dropped support for natively booting Mac OS 9 and only support Mac OS X. Through a lot of hard work the folks at have been able to get Mac OS 9 booting on most of these systems. Below is a compiled list of tutorials from my own experiences, and the others from MacOS9Lives.

Unsupported Mac OS 9 Install Disc Image

There are a number of disc images available for multiple models at I recommend burning these CDs with an application such as Toast Titanium.

Models known to work

  • Mac Mini - All G4 models
  • PowerBook G4
    Best Models: [5,1], [5,2], [5,3], [5,4]
  • eMac G4 (1.25Ghz)
  • Power Macintosh G4 Mirror Drive Doors (1.25Ghz FW800)
  • iMac G4

Hardware Support

Most of these machines have newer hardware that was never available for Mac OS 9, therefore there are missing drivers and system components - not all devices will work. The most common issues are with unsupported sound cards, video cards, Bluetooth, and Airport cards. The most success has been achieved with machines that have an ATI Graphics card/chip-set. Graphics acceleration is unavailable unless you have a graphics chip-set that is officially supported under Mac OS 9.


Before you install Mac OS 9 on your machine, your Hard Drive must have the Mac OS9 disk drivers installed. You can do this with either of the following methods:

  • Boot from an OSX install CD, open ‘Disk Utility’ and partition/erase your HD with the ‘Mac OS Extended’ format. Ensure the option ‘Install Mac OS 9 Drivers is ticked!
  • Connect the Hard Drive into a computer already running Mac OS 9 and re-partition/format it with the application ‘Drive Setup’

Booting into Mac OS 9

This is achieved by performing some modifications in Open Firmware, and tricking your machine into thinking it has a different CPU version (This does not effect performance in OSX).

  1. Boot into Open Firmware by holding Command + Option + O + F when turning on or restarting your machine.
  2. Once Open Firmware has loaded you will need to open the NVRAM editor by typing nvedit, and then press Enter.
  3. Open the CPU device by typing the following:
    dev /cpus/PowerPC,G4@0 then press Enter
  4. Make the following modification to the cpu-version property:
    80010201 encode-int " cpu-version" property
  5. Enter device-end to close the CPU device.
  6. Press Control + C to close the NVRAM editor.

Note: If there is text present after you open the NVRAM editor, these are settings that are already stored. You can either clear this by holding the delete key, or press the down arrow key for a new line, then you can start typing. When you open the editor you can think of it like you're viewing a document, but you're only seeing one line at a time. You can scroll through lines with the arrow keys. Once you're on a blank line you can enter any settings you'd like to add.

Performing the above only allows you to boot into Mac OS 9 temporarily. These commands need to be stored in the NVRAM so they persist between boots. Running the commands below will store this information in the NVRAM and restart the machine.

setenv use-nvramrc? true
reset all

Your machine will restart and you should now be able to boot from the Mac OS 9 For Unsupported G4’s CD from

Any data stored in the NVRAM will be erased if the machine loses power (e.g. the main power cable is disconnected from a wall outlet/power adapter, or has a flat battery. Since this is a lot to type each time you lose power, a better way of performing the above is to write everything into a script, and tell Open Firmware to run it at boot. Now if you lose power you only need to remember one line to enter into Open Firmware.

Writing an Open Firmware Script

Open Firmware Scripts can be created with the application ‘SimpleText’, or any other text editor that will allow you to save .txt files without any rich text content. Open SimpleText and add the following to your new document.

\ comment
dev /cpus/PowerPC,G4@0
80010201 encode-int " cpu-version" property
boot hd:,\\:tbxi

The beginning of the script must contain an Open Firmware \ comment, followed by a carriage return cr.

The last line sets the boot device to the default HD so the machine continues to boot after running the script.

Save the file to the root/base directory of your hard drive and call it ‘bootscript’.

Some machines have incompatible soundcards and will crash or refuse to boot OS9 after the above steps have been taken. If this happens try adding the following to the NVRAM, or your script.

dev /pci@F2000000/mac-io/i2s/i2s-a
" screamer" encode-string " compatible" property 

An example of this would look like the below:

\ comment
dev /cpus/PowerPC,G4@0
80010201 encode-int " cpu-version" property
dev /pci@F2000000/mac-io/i2s/i2s-a
" screamer" encode-string " compatible" property
boot hd:,\\:tbxi

Mac OS 9 does not have good thermal management for unsupported systems. If you're worried about elevated hardware temperatures under Mac OS 9, see the article Controlling System Fans with Open Firmware. You can combine both scripts to make things easier.

Installing from a CD

After booting successfully into Mac OS 9 you will need to install the system onto your hard drive. It’s a good idea to erase your HD with ‘Drive Setup’ if you don’t have anything important on it already.

If you install from one of the MacOS 9 Lives CD images start the restore process and follow the instructions. Once the restore process has completed DO NOT restart your machine. Open the ‘System Folder’, then ‘Extensions’ and remove the ‘Multi Processing’ folder. Move this to your desktop or delete it. This extension causes some incompatibilities and will freeze the system during boot.

If you install from any other CD/image the same step is recommended.

Once the system is installed and you have removed the ‘Multi Processing’ folder, restart the machine.

Video/Monitor Settings

When you've booted into the newly installed system you may be stuck with a small screen resolution.

If your machine has an ATI Graphics chip-set it is highly recommended that you add this driver modified by darthnVader (alternative link) from Mac OS 9 Lives. This adds better compatibility with more resolutions and color depths. Expand the file with Stuffit Expander and move the extension to your ‘Extensions’ folder, which is located in the System Folder, then restart the computer.

If you've still got a small screen resolution, or limited colour set open the ‘Monitors’ control panel and adjust the monitor arrangement. First drag the menu-bar from the smaller screen to the bigger screen. This sets the default desktop. Next, change the screen arrangement by moving #2 to the left before #1.



You should now hopefully have a working Mac OS 9 system!

Special thanks to:



02 May 2022

Hey, followed the guide for a Powerbook G4 (5,2) but after installing the ATI drive, when OS 9 boots, it now just freezes. It boots, gets to the desktop then freezes, cant moving anything but the mouse cursor. Any idea why?

Greystash - Admin

02 May 2022

I've come across this also and I think there's a bug involving some of the ATI drivers. Try this:

After booting wait at the desktop for a while in the frozen state. After waiting, open the Force Quit prompt (command + option + Esc). The prompt should ask you to force quit an ATI utility (because this is what's currently hanging the system).

If you don't get this wait a little longer after the next restart.

Once you've booted successfully into the system, disable all NVDIA drivers, and try disabling/toggling some ATI drivers. I can't remember which one causes the issue but it's not going to make much difference disabling some/all since GPU acceleration isn't available anyway. The modified Jasper driver is essential for screen resolution and color support.


23 January 2022

Greystash, Ok I tried the above script for the PowerBook G4 DLSD and though it is visable when I hold down the option key, once it loads the computer just goes off, meaning it shuts off. I have feeling the video chip may not be compatible with OS 9 at all. I need to know if you were able to get OS 9 to boot off the last G4 PowerBook Dual-Layer Superdrive models. I tried the screamer and it would not work either. Perhaps the last model G4 DLSD 17 and 15 inch DDR2 models are not working due to the video and or DDR2 memory ?

Greystash - Admin

29 January 2022

Hi Roman. After checking my model I noticed that it's not the DLSD model, instead it's the PowerBook 5,6.

If yours crashes immediately after selecting the boot device then I would assume it's an issue with incompatible RAM (DDR2). I don't think there were any machines supported by OS9 that used DDR2 memory.

If the system begins loading, and then crashes then it could be a video issue. The GPU is unsupported but may work with the modified ATI driver made by darthnVader from MacOS9Lives. This would need to be moved to the Extensions folder of the System Folder you are trying to boot.

Good luck!


19 January 2022

Will this ever work for a G4 PowerBook DLSD 15/17 inch ? That is 5,8 PowerBook G4 15 INCH.

Greystash - Admin

21 January 2022

Hi Roman, as far as I'm aware it does work with the screamer fix mentioned above. I managed to get it working on an overclocked 1.8Ghz model (1.67Ghz 15" model although I can't remember if it was DLSD).
The main issue is that these later models have a USB track pad that is unsupported by OS9, so the tracking is incredibly slow making it barely usable. If someone were able to write a driver for this it would be by far the best portable unsupported Mac OS 9 machine. If you're willing to use a mouse instead it would be fine.

abdalwahab orabi

02 June 2021

i flow you instructions on my ibook 12 early 2004 and i works great except screen resolution stuck at 640*480 ant the link you provided is broken and i can not fix the screen resolution

Greystash - Admin

07 June 2021

Hi there, I've edited the page to explain the monitor/resolution problems in more detail. I've also added an alternative link for the video driver, so see above for these edits.

abdalwahab orabi

02 June 2021

speakers working great but screamer fix can not open the link because it is broken is there any other link or way of explanation by the way "you may be stuck with a small screen resolution. If this happens open the ‘Monitors’ control panel and adjust the monitor arrangement. Try swapping the right-hand screen over to the left etc. To change the default desktop, drag the menu bar across to the desired screen." i did not understand what you mean

Greystash - Admin

07 June 2021

If the speakers are working fine then it's likely you won't need the screamer fix. If they aren't functioning correctly you don't need to download anything, just add the screamer fix code detailed above to your Open Firmware script.


29 May 2021

I followed your guide and now have a working MacOS9-capable eMac 1.25GHz! The sound only comes out from one speaker though, i don't know if a fix exists.

Greystash - Admin

29 May 2021

Hi there! That's great news, congrats! Do both speakers work correctly under OSX?
If they do it might be a driver compatibility issue under OS9.

If you haven't tried the "screamer" fix mentioned above you could try that, otherwise if it's already present in your script/NVRAM you could try removing it.

Also, this probably isn't the issue but check the speaker balance in the Sound control panel.


23 February 2021

Wow :) !

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