Mac OS 8.6 for (some) Unsupported G3s and G4s

[LightBulbFun]

Thanks for the heads up. I've tweaked it to match your version.

ahh its still not quite right im afraid

this is what you should do

dev /cpus/PowerPC,G4
000c0206 encode-int " cpu-version" property
unselect-dev

and if you want to actually see the changes before and after you would want to do it like so

dev /cpus/PowerPC,G4
.properties
000c0206 encode-int " cpu-version" property
.properties
unselect-dev

and also note the actual name of the CPU in Open Firmware, most stock G4 systems will be just "PowerPC,G4" but if you have something like a 7447-7448 CPU upgrade and depending on who's firmware patcher your using the name might be "PowerPC,60?" for example and if you have a multiple CPU system you will have to do it for each CPU, and dont forget you might likely need a patched multi-processor extension (or if using a 7455 just use the one from 9.2.2? I dunno, never really tested it!)

if your not sure you can just do a ls /cpus and see what name is read back

 

[RandomSeed]

Thanks for this! Will give it a go.

My hosting service isn't great sorry. People in the Americas might find the connection drops. All I can say is sorry, but if you keep trying it eventually should complete.

I had the connection drop issue but used wget via terminal and was able to handle the connection issues.

 

[Figgy2112]

Tried On My 2001 600mhz iMac G3 with the stock 16mb vram ati card, Seemed to read it fine and boot but no video, just a white screen even tho it looked and sounded like things were reading/working

 

[bamdad]

Evening folks.

Apple released the early G4s, Yikes and Sawtooth, with special, updated versions of Mac OS 8.6. I'm not sure if people are aware, but @LightBulbFun did some excellent work here to produce a modified version of the Mac OS ROM file, that goes in the System Folder, to enable this special version of 8.6 to be booted on unsupported machines including the Pismo, Gigabit Ethernet G4, some DA G4s, some extra iMacs that are not usually supported, some iBooks, probably the Cube and perhaps some early PowerBook G4s? The requirements are that the machine needs to have an old enough processor and be similar to an officially supported machine. Machines with the G4 7450 processor and newer are not immediately supported without some further fiddling in OpenFirmware.

I decided to take this modified ROM file and wrap it up in a modified version of the Mac OS 8.6 installer CD. I'm not going to lie, while most of it was easy, getting the Installer application on the CD to actually install the modified file was way more tricky than I expected. Yes I tried replacing the file in the two tomes it appeared in. That lost me about 5 hours of my day. Yes I tried editing the install scripts, it wasn't possible to convert them between their compiled state and editible state easily, given my poor knowledge of the Apple Installer SDK. Right. Anyway.

Make sure your computer is running the most up to date firmware. I forgot to and it caused me issues on my GigE G4.

Features of my CD image :

• This CD should boot most supported unsupported machines, by holding the 'C' key.
• The firmware updates you might need are included on the CD.
• An Apple made Machine ID spoofer Control Panel is included in utilities in case you need it.
• The installer works and provides a system with the modified Mac OS ROM file.
• The restore application works and restores an image including the modified Mac OS ROM file.

Unintentional features :

• For some reason, sometimes Pismos (perhaps other similar machines) power off when they start loading the desktop from a CD. Installed systems work just fine, but you might need to boot from another disk while you install.

Things I did :

• I modified the restore image to add the Mac OS ROM file.
• I modified the CD System Folder to add the Mac OS ROM file.
• I added the Machine ID control panel in Utilities (but not the System Folder, I probably should have).
• I removed the machine specific white-list from the installer program so it will launch on absolutely any machine, regardless of whether it is appropriate or not.
• I made a new installer script, and tagged it on the end of the 8.6 update in the Installer, so that it silently swaps in the modified Mac OS ROM file without bothering the user.
• I added a load of firmware updaters in a folder.
• I added some ReadMes for clarity.
• I messed up the order of the icons on the CD by accidentally clicking "Clean Up" when I didn't mean to.

I have tested on a Pismo and on a GigaE G4, but would appreciate feedback on what it works on. This isn't a magic bullet - this will not work on a G5, or a Plus, see the thread linked above for OpenFirmware hacks to get 8.6 running on a QuickSilver or MDD, but that won't work right out the box, so really only play with this if you have a Pismo, early TiBook, G3 iBook, Graphite G4, G3 iMac or Cube.

https://elephantandchicken.co.uk/downloads/CDImages/Mac_OS_8.6_Unsupported_G3_G4.zip

My hosting service isn't great sorry. People in the Americas might find the connection drops. All I can say is sorry, but if you keep trying it eventually should complete. The download is about 400MB.

Consider the software to be experimental. It might not work, but if it does

Please don't ask for changes, they're likely impossible and I've had a really crap day.

hey, so.. i tried this on my pismo but any way i try to boot it (directly from CD, or by copyint the system folder from the restore image to a partition and copying the ROM over to it) it just gives me a frozen mouse cursor before even the happy mac..

my firmware is 4.1.8f5. is there anything i'm missing?

 

[bamdad]

hey, so.. i tried this on my pismo but any way i try to boot it (directly from CD, or by copyint the system folder from the restore image to a partition and copying the ROM over to it) it just gives me a frozen mouse cursor before even the happy mac..

my firmware is 4.1.8f5. is there anything i'm missing?

okay figured it out. having a CF card adapter in the PCMCIA slot makes it crash hard before even starting the boot process.. just for future reference

 

[bamdad]

after some testing:
- os starts with 'finder unexpectedly quit' but works anyway
- system profiler never opens
- machine randomly shuts down sometimes (not just on boot)
- battery works but is not detected ('left bay is empty')

otherwise everything (sound, network, native resolutions, clamshell mode, even 3d acceleration) works well - at least on my pismo..