This page is a wiki. Please login or create an account to begin editing.

6 posts / 0 new
Last post
reddrag0n's picture
Joined: 2015 May 16
OS 9 on FW800 MDD

Well, i can honestly say that all MDD's can boot OS 9. Took a little digging, but i found the answer. Thanks to a user called "blitter" from macos9lives, the FW800 MDD can boot native OS9.,762.msg3962.html#msg3962

Created an account here just to pop in and say that I have just solved this problem on my own retail MDD G4 FW800. My G4 now dual-boots between OS X Tiger and Mac OS 9.2.2, and both systems are recognized by the Startup Disk control panel. I had formatted its internal drive by using a surrogate iBook + USB enclosure and OS X Jaguar, allocating 1GB at the beginning of the drive for an OS 9 partition, leaving the rest for OS X. I also checked the "Install OS 9 drivers" box in Disk Utility so that the drive could be booted later on. I then installed OS X Tiger first as an escape hatch in case of OS 9 instability, though so far with the exception of a third-party SCSI card preventing it from booting, it has been running without any problems.

Essentially what locks native OS 9 support out of these machines, as has been suggested above, is that Open Firmware does not recognize "Mac OS ROM" as a valid tbxi file as of at least version 4.6.0, which is what the FW800 ships with. Since the FW800 and the earlier FW400 are so close in spec, I suspected that an earlier version of Open Firmware from the FW400 model would be close enough to at least boot the FW800 into OS X. Fortunately a firmware update is available from Apple for the FW400 models to fix a fan issue, bringing their firmware to version 4.4.8f2. However, Apple's firmware updaters refuse to flash the Boot ROM unless the current version is older than the desired upgrade. So, I worked around that by forcing an upgrade through Open Firmware itself. Here's how to do it on a FW800 with OS X already installed on a second partition:

- Download and install the 4.4.8f2 updater from
- Open the bundle by right-clicking (or control-clicking) on the file inside /Applications/Utilities and choosing "Show Package Contents."
- Navigate to Contents/Resources and drag the "Firmware" file to the root of your startup disk.
- Make note of the partition number of your startup disk-- this is important for the next steps. On a freshly-formatted drive with OS 9 drivers, the first visible partition is 9, which in my case meant my second visible partition with OS X installed was partition number 10.
- Reboot the Mac and hold down Command-Option-O-F to boot to Open Firmware.
- Enter the following two commands, substituting your partition number after the "hd:"
load hd:10,Firmware
- With luck, the white Open Firmware prompt will disappear and you'll soon see an OS 9-style progress bar at the bottom of the screen as the Boot ROM is being flashed.
- After the Mac automatically restarts, install OS 9 using the special version for the MDD FW400 (OS9General.dmg). The OS 9 System Folder should be visible and selectable using the Startup Disk preference pane.
- Enjoy. Smile

Only one problem is faced with this approach, and this is what is stated...,762.msg4078.html#msg4078
In OS9 the stock Firewire 400 ports does not work anymore! Only the FW800 does! Sad

A quick test under OSX prove it happens on OS9 only, the two FW400 ports works well both under 10.4 and 10.5 so this could be only a driver issue, maybe in OS9 the drivers are rigidly mapped to hardware resources and if the phisical address is changed (like flashing a machine with a different machine firmware) they do not found their way anymore. So this is the first serious problem of this firmware downgrade but if you add a combo PCI card USB/Firewire this issue can be less problematic as it could seem in first place.


MikeTomTom's picture
Joined: 2009 Dec 7

Many thanks for this post (now made sticky). It will serve as a practical guideline to others who are able to and wish to pursue this course. Thank you.

MacTron's picture
Joined: 2012 May 4

Be aware that this info is obsolete.
You only need a special ROM modded by iMic and nanopico that allow to Mac Os 9 to boot in most of "unsupported" G4s ...

ristar's picture
Joined: 2016 May 27

How are you able to install the new firmware when your OS 9 partition is its own hard drive separate from the OS X drive? I can't get the files in the drive to read as a bootable drive even after properly formatting it.

MacTron's picture
Joined: 2012 May 4

No firmware update is needed. This info is obsolete. As I told you.
You only need a special ROM modded by iMic and nanopico that allow to Mac Os 9 to boot in most of "unsupported" G4s.

sstaylor's picture
Joined: 2016 Aug 26

Link, please?