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[sfurtaw]

Hi all!

Sorry to resurrect this thread - I've been reading through lots of threads on this forum trying to figure out how I can get OS 9 booting on my iMac G4 flat panel, and I was able to get it to boot and install. There were two limitations though - there was no audio and it was limited to 256 colors.

Was there ever progress made on getting those two features working properly on a G4 flat panel? I distinctly remember reading a thread about using a MDD install disc, but I'm completely lost as to the details of that (and if it worked...)

I can start a new thread if that makes more sense.

Thanks!

[Rainier]

I'm curious about a couple of things pertaining to unsupported OS9 install on a 1,25 iMac USB 2

has imic's updated ROM been placed on OS9Lives and, if so, where might it be? I know: his discussion was posted in 2014.

Going to his website, cited in his posts, brings up a screen that asks for clicking on a nonexistent button OR a requirement to install an app, neither of which actions I trust.

Or has that ROM been incorporated into an install ISO?

Multiple thanks.

[DieHard]

I'm curious about a couple of things pertaining to unsupported OS9 install on a 1,25 iMac USB 2

has imic's updated ROM been placed on OS9Lives and, if so, where might it be? I know: his discussion was posted in 2014.

This is what you seek...
ISO CD Image
Contains Modified ROM, No Crazy Commands to type, Just Boot and Install !
http://macos9lives.com/smforum/index.php/topic,2143.0.html

[Rainier]

Aha!

I see iMic's name there on the download page.

My wife tells me that "Men cannot find things." I thought I'd prove her correct yet again.

Thanks for your assistance. I pick up the iMac on Friday, arriving home Saturday and will probably begin performing dubious actions on it that evening or Sunday. I do enjoy this stuff, even though my sense of adventure far exceeds my understanding.

[Rainier]

Let's see. OS9 worked fine under Tiger. Thought I'd try Sorbet Leopard on my iMac: 17" FP; 1.25 GHz PowerPC 7445 CPU; "USB 2.0"

(what does USB 2.0 mean in real terms?? 1.0.)

It's a dog, not a greyhound or whippet, and OS X is not a favorite either.

So I thought "Why not put OS9 native on the iMac?" something I am finally getting around to doing. (Life has a way of interrupting the important stuff)

Using Firewire between my MDD running OS9 and the iMac I got OS9 installed. It boots, then screen goes black. Not a new problem for anyone on this thread.

A few entries prior to mine one of you--ZencadE--used some OF commands to get a different iMac G4 to boot into OS9.

My question is this:  May I use the same OF commands to achieve the same end on my hardware, which is slightly different than his?

I've read the multiple warnings about not screwing around with OF lest I brick my iMac. The iMac, while heavy, is too large to serve as a paper weight.

Any advice?

I've learned much from you-all. Many thanks.

[Rainier]

On a whim I went into the System folder via Firewire from the MDD and deleted every extension (saving them to a separate folder, that is.)

Tried to boot and, voila - Mac OS9 boots. A bit crippled; but I'll sort that.

I had already moved the multiprocessing extension out prior to the above.

Scouring this forum provides much fodder which, when carefully chewed and pondered and ruminated, yields possible solutions. In this case I'm gratefully satisfied with the fodder I consumed. Again: thanks, all.

[t0t4r4]

This is what you seek...
ISO CD Image
Contains Modified ROM, No Crazy Commands to type, Just Boot and Install !
http://macos9lives.com/smforum/index.php/topic,2143.0.html

Unfortunately the link is dead (is it since the ownership change?)

@rainier
Would it be possible to be know which OF commands were run and which image actually booted OS9 ?

Thanks all !

[aBc]

Try this?
http://macos9lives.com/smforum/index.php?action=downloads;sa=view;down=3

[t0t4r4]

Try this?
http://macos9lives.com/smforum/index.php?action=downloads;sa=view;down=3

Works, many thanks !

[bebopbeluga]

This is what you seek...
ISO CD Image
Contains Modified ROM, No Crazy Commands to type, Just Boot and Install !
http://macos9lives.com/smforum/index.php/topic,2143.0.html

So what you link here will boot an iMac G4 800MHz 15 inch model? Is all hardware supported?

[indibil]

I'm curious about a couple of things pertaining to unsupported OS9 install on a 1,25 iMac USB 2

has imic's updated ROM been placed on OS9Lives and, if so, where might it be? I know: his discussion was posted in 2014.

This is what you seek...
ISO CD Image
Contains Modified ROM, No Crazy Commands to type, Just Boot and Install !
http://macos9lives.com/smforum/index.php/topic,2143.0.html

Hi, neither of the last two links work for me. I'm trying to install OS9 on a 17" iMac G4 1GHz USB 1.1.

Is the link still available?

[indibil]

@Bolkonskij and @Knezzen, this link isn't working. Can you recover it?

http://macos9lives.com/smforum/index.php?action=downloads;sa=view;down=3

Thank you.

[Knezzen]

No need to recover the old download boards. The Mac OS 9 install images have been moved to here. They are the exact same images previously hosted at the link you want recovered

[indibil]

Well, none of those downloads have worked.

[aBc]

You may want to review Greystash’s rundown on his approach here:
https://mac-classic.com/articles/mac-os-9-on-unsupported-systems/

This thread here sorely needs review and severe clarification (and
has needed this for quite sometime). The “easy” file referenced from
DieHard, I believe refers to USB 2.0 equipped models - but I could
definitely be poorly mistaken. (Again)

I’ve mentioned before that I’ve got the 20” 1.25 GHz model, that
because of its GPU (there were two types?) that it cannot run
OS 9. Even as in the abridged chart below notes that it can?

And why no blue outline on the G4 / 800 17-inch (Flat Panel)?



So maybe here’s a little project for someone to review and update
this topic and hopefully clarify what approach works with which?
But for now, DO check Greystash’s rundown mentioned above.
Yeah, I don't like using Open Firmware either, if avoidable.



And again, if you cannot read the text in the images above,
temporarily switch your Forum theme to the old "Blu" theme. 

[indibil]

Hi, I just finished setting up my Super iMac G4, it was fun:

https://rosysumenteinquieta.blogspot.com/2025/07/hace-unos-dias-os-mostre-con-imagenes.html

Now I just need to add the SSD, but before that, I've been trying to install OS9 without success. I've tried every .ISO I could find, every Mac OS ROM I could find, and I've had no luck. I'm looking for a way to boot into OS9 without having to run Open Firmware commands; I don't want to have to figure out how to boot into OS9 again once the battery dies.

For the iBook G4, I was able to install OS9 with a custom-made Mac OS ROM:

https://macintoshgarden.org/apps/mac-os-922-boot-file-ibook-g4

Does anyone know how to modify a Mac OS ROM so my iMac G4 can boot OS 9? What information should I provide?

Thanks.

[Greystash]

Hi Indibil,

Congrats on the upgrade, that's a fast machine!

I haven't had much to do with the unsupported installations for a while, but from what I remember a lot of the later G4 models have an unsupported sound device, and require the "screamer" fix to trick it into thinking the current device is compatible. This does require using Open Firmware (at least once).

My suggestion would be to follow the steps in that post with the "screamer" fix. When it boots you can write a script so you don't need to deal with Open Firmware every time (guide also referenced in that post). If you write a script with the Open Firmware commands, you only need to set the boot device to the script in OFW and it will run the commands automatically.

I've been planning to look at modifying the Mac OS ROM to run some of these commands, but I haven't had enough time recently.

A while ago I tried messing around with OFW to bring graphics support to the unsupported iMacs but was unsuccessful - a post you may find interesting/might want to do some experimenting with:
https://macos9lives.com/smforum/index.php?topic=7054.msg54720#msg54720



In summary, boot into OFW and enter these commands as a test. It's likely you need to apply the "screamer" fix which I don't think is present in any of the Mac OS ROMs contained in the ISOs.

Code: [Select]

nvedit

Code: [Select]

dev /cpus/PowerPC,G4@0
80010201 encode-int " cpu-version" property
device-end

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

Press CTRL + C to exit the NVRAM editor.

Code: [Select]

nvstore
setenv use-nvramrc? true
reset-all

If this works, then copy it into a script.

If you wanted to wait, I might try modifying one of the ROMs tonight (but no promises). I don't currently have any machines to test with right now

[indibil]

Code: [Select]

nvedit

Code: [Select]

dev /cpus/PowerPC,G4@0
80010201 encode-int " cpu-version" property
device-end

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

Press CTRL + C to exit the NVRAM editor.

Code: [Select]

nvstore
setenv use-nvramrc? true
reset-all

If this works, then copy it into a script.

If you wanted to wait, I might try modifying one of the ROMs tonight (but no promises). I don't currently have any machines to test with right now

Wow, thanks a lot! I'll try, but I don't know if I'll be able to write a script that runs at boot time. I'm not sure how to do this.

If you could make a modified ROM, that would be perfect! I can wait; there's no rush. If I can provide you with any information you need about the iMac, let me know how I can get it and I'll help. I guess using a 7447 instead of a 7445 doesn't change anything.

Thanks!!!

[indibil]

I have tried editing nvedit but when I start and press ALT, only the OSX partition appears