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MacOS 8.6 on "Sawtooth" G4

As an aside, now that we know that almeath's G4 is really a Gigabit Ethernet model and not a Sawtooth, all of my speculation above about the effect of boot rom v3.3.x on a Sawtooth can probably be ignored. I am now leaning toward the belief that boot rom v3.3.x first appeared with the Gigabit Ethernet G4 and was not used on any Sawtooth. As I noted above, the Japanese site I found seems to indicate the last boot rom version used on the Sawtooth was v3.2.6. However, the site also seems to imply that only the boot roms up to v3.2.4 support 8.6 booting. I wonder if boot rom v3.2.6 is the firmware that came on the later Sawtooth motherboards that supported dual CPUs. Thus, it may still be an open question whether the presence of a dual CPU motherboard effects the ability to boot into 8.6 (as well as whether it is safe to try to reflash to an earlier firmware version).

Again, we still need all Sawtooth owners to report what Uni-N revision their motherboard is as well as the boot rom version.

 
almeath,

Even though we now know that you have a Gigabit Ethernet G4 that probably can't run 8.6, it would be nice if you would make the Sawtooth 8.6 system files available for those Sawtooth owners who would like to continue with this experiment. In fact, the Sawtooth 8.6 system files may be useful on other macs running 8.6. Since this was probably one of the last releases of 8.6 that Apple made, in theory it may contain bug fixes that they did not otherwise make available. Thus, anyone running the Sawtooth 8.6 system folder would in theory be running one of the most up-to-date versions of 8.6 available.

I would still be interested in seeing a detailed comparison between a retail 8.6 install and a Sawtooth 8.6 install to see exactly what was updated and what wasn't.

 
If anyone needs ROM 2.5.1 or an ISO image for an entire G4 system restore CD with Mac OS 8.6, please PM me and I will be happy to provide you with the links.

The ISO is about 380MB compressed in a ZIP file.

 
Thanks ealex79, I just replied to your PM.

We are referring to a hybrid system folder that was constructed using Mac OS 8.6 off an iMac restore CD and ROM 2.5.1.

I'm certain that it would have worked if I actually had a sawtooth and not a gigbit ethernet G4. As we now know, M5183 is most likely an identification number used for the cases of several G4 models, including both the sawtooth and gigabit ethernet models.

In any case, I'm going to go search for a second hand AGP G4 on eBay. This time I'll make sure I'm being sold a real sawtooth! [:)] ]'>

Again, if anyone needs the ROM / system CD, just PM me.

 
make sure it has an internal 6 pin FireWire port, then you know it is a Sawtooth. Oh, and the GBE models have a tall rough silver coloured heatsink on a chip behind the ethernet port while the Sawtooth does not.

 
I finally managed to obtain, from a second-hand dealer, a G4 sawtooth that boots up in 8.6. Yes, it is very fast. [:)] ]'>

To be safe I sent the dealer a copy of my boot CD, which they tested in the machine before sale.

It's an AGP system with boot rom 2.6f1 so I assume it is an early AGP model. The case looks identical to my Gigabit G4 except that the panel on the back has a blue & white wavy 3D pattern (I don't know what you call it). On the Gigabit the panel is a matte gray color. Otherwise, the configuration of plugs looks to be identical on the two units.

 
I'd say you have a Gigabit Ethernet G4/400.
And they're not exactly rare - it was the low cost, "no frills" version of the Gigabit G4, for people who couldn't afford/didn't need dual processors.
Click to expand...
And 50 more megahertz was too costly to upgrade to?

 
I would not be surprised - remember, this stuff was expensive back then, and that wasn't helped one bit by the fact that Motorola was having a lot of trouble putting out fast G4s, hence why the G4 was stuck at 500 Mhz for the longest time - and we were lucky to even have that!

 
To the 500 Mhz G4 barrier:

Thats why the PPC 7450 was used in the 667 and 733 Mhz G4 DA.

An interesting note is that the lower price Digital Audio model include a PowerBook CPU called 7410 that can use half its cache as RAM and may be better at overclocking because it runs cooler ,which I didn't measure yet.The 7410/7400 can do some calculations faster than the 7450 at same speed but have no L2 cache on the chip but on the CPU module at lower clockrate.Dual GBE or DA owners can test this.The same off-chip caching concept was used in the Pentium II and the earlier Slot I pentium III(Katmai).

To the topic:

It may prove useful to have something like the Linux Flashrom program that can identify Flash ICs disable protection lines and read or write images.

My 2 New World Macintoshs have generic 1MB roms that I have identified, have the model numbers not at head.

 
I just burned the os 8.6 disk, put on my g4 ( i have my g4 upgraded to the latest firmware), reboot.. and worked!.. now i going to install it to my HD.

 
Thanks to almeath, I could test it for myself. Here is my story:

I tried to boot an existing 8.6 installation from my g3 b&w on the g4 sawtooth (it has the onboard firewire port) - but had no success. "trap not implemented" + bomb. ROM file was 1.6; changed the ROM file to something newer, originating from OS 9. again: no success - "trap not implemented". even with extensions off.

Once I had a Powerbook G4 1GHz, the last model booting OS 9.2.2; it had the same symptoms, until I got the right ROM file, which was definitely newer than anything you could get via updates. later I found a really new ROM file on a CD which came with an iMac and Panther. There is a classic environment "onboard" which has ROM version 10.2.1 and dates from April 2003...

Back to Sawtooth! Given this experience and plenty of information from the apple info sites regarding model bootability (http://docs.info.apple.com/article.html?artnum=25114) it is as clear as can be: Sawtooth needs its own ROM file!

Thanks again to almeath - I got his file. and tried again. This time sadly I didn't even get the bomb... it stopped just with a grey screen. I couldn't believe it, swapped graphic cards (different Rage128 Versions, even PCI) - still no success.

Regarding all the Firmware flashing discussions above, I thought I should try to backflash to an earlier version. My Sawtooth got the newest Firmware available once a while ago. It has Boot Rom Version 4.2.8f1 built on 10/11/01 ! So, was 8.6 bootability disabled through firmware?

I remembered, I had tested a Newertech CPU Upgrade this summer in this machine, and perhaps you know, there are some firmware modifications necessary to boot this new 7448 PPCs. So I removed the firmware patches, but had still no success. There is some code in NVRam, which has to be activated to boot either OS 9 or X with this 7448 CPU. This CPU is not installed now, instead it's the original 400 MHz G4. so no 8.6 boot - d*** machine!

Wanting to give up, I had a last idea - what's about resetting this NVram? booted to open firmware, typed reset-nvram, then restarted - et voilà: happy mac with 8.6 big on screen! successful booting! Now I had my original 8.6 installation from g3 b&w running on my sawtooth with just this 2.5.1 ROM file!

WOW! :-) thank you, almeath!

conclusion: OS 8.6 booting is *not* deactivated via firmware update, so there is no need to backflash. It's the ROM file which has to be the right one. and zapping PRAM still helps sometimes...

 
Well I finally tried booting my Sawtooth in 8.6 using Almeath's file which I burned to CD. Since my sawtooth had a bootrom of 4.2.8f1, I assumed that 8.6 booting was no longer possible. However, after reading isokrates post about resetting the nvram, I thought I would give it a try.

First, a little history about my 400mhz sawtooth. I got it used without a hard drive and no install cd. Thus, I don't know if was one of the early 8.6 sawtooths. I put in a hard drive and installed 9.2.2. The firmware had already been updated to 4.2.8f1. It had not been used for quite some time and the pram battery was dead which I replaced.

Now on to my 8.6 boot tests. Before trying the nvram reset, I tried booting using the 8.6 install cd. The 9.2.2 Startup Disk Control Panel seemed to recognize the 8.6 cd as a valid system and when I restarted it did in fact start up under 8.6. I then got 2 messages. The first message stated that full usb support would not be available. I think this message is to be expected given that the 8.6 system on the install cd is not a full install. The next message stated that a desktop folder could not be created and that I should unlock the disk. When I clicked OK, the mac rebooted and I again started up in 8.6 and got the same messages. Since it was clear that I was stuck in a loop, I ejected the 8.6 cd and let the sawtooth boot into 9.2.2 using the hard drive. I am assuming that I did something wrong when I burned almeath's file to cd. Has anyone else tried booting using this file after burning it to cd?

I definitely wanted to confirm that it could boot into 8.6 so I thought I would try using the install cd to install 8.6 on an external scsi hard drive I have. When I pulled it out, I discovered it already had a retail 8.6 install already on it. I didn't want to erase this install, so instead of doing a new full install, I just copied over the special sawtooth mac os rom file from the sawtooth install cd and to play it safe the updated Startup Disk control panel as well. I then went into the 9.2.2 startup disk control panel and chose the external 8.6 hard drive and rebooted. The sawtooth then successfully booted into 8.6.

My conclusion: I think isokrates is correct. There must be something in the pram/nvram that prevents booting into 8.6. In my case I didn't even have to reset the nvram. The dead pram battery that I had would definitely have the same effect as resetting the pram but I don't know what effect it has on nvram. Thus, I am leaning to the theory that whatever was preventing 8.6 booting was probably in pram rather than nvram.

I didn't do any benchmarking before I removed the external hard drive, but 8.6 did feel slightly faster than 9.2.2. Eventually I may install a second internal hard drive for a 8.6 install.

 
Hi all, please anybody could share the Mac OS ROM 2.5.1 or the os 8.6 for my Sawtooh? I have 8.5 original, but it wont run :( thanks in advance.

 
Hi All, as one can plainly see, I'm new to this forum, but not new to the mac. Been a beta tester for many years, Virtual Wings Pro, Fly! II, A-10 Attack, Quicken 3, Falcon 4, etc., just to name a few.

Just recently, my wife picked up a mint Sawtooth G4 500 (AGP) fm MIT, and now I have something to play on since OSX had taken over our house. Got most of my ancient sw stored on a beige G3/333, as well as zips & CDs & DVDs.

Now that the sawtooth is cleaned up, dusted off and rocking pretty solid w/ 9.1, I would like to add a 2nd drive w/ 8.6. I have several mac systems disc, but none that will boot the G4 (AGP), can someone find it in their hearts to help a brother out ;)

From reading thru this thread, and google non stop, I cannot find the 2.5.1 ROM. If anyone can be of help, who has gotten the Sawtooth to boot into 8.6, please help me out? If you have a working sys ƒ, this would be ideal ... Maybe I could burn a few beta CDs, or other hard to find programs in my inventory. Just a thought. Please help? Please contact me?

I'm hoping to pull all my old mac games & simulations out of retirement. They have been boxed up in the original boxes for years.

 
Just an update.

I replaced the original 400mhz cpu in my Sawtooth with a OWC 1.5ghz G4 upgrade (that I downclocked to 1.4ghz). Now it won't let me boot into 8.6 anymore. When I am booted into 9.2.2 and go into the startup disk control panel and choose 8.6 and restart, all I get is a white screen. At that point, the only way to get back to 9.2.2 is to use one of those emergency key sequences at startup that forces the mac to boot from a different volume than the chosen startup volume.

 
Desperately in search of Mac OS ROM 2.5.1 to get 8.6 running on a PowerMac G4 SawTooth. I have scoured the abandonware archives and used my status as Apple Certified tech to check every currently relevent diagnostic download, I can not find this f@#$'n file anywhere.

I have some old data to access with compressed resource-forks and thought I'd build up the ultimate 8.6 machine... got a Sawtooth, ATX PS, QuickSilver 933 processor... figure I'll hack off the 2nd IDE bus and drop in a PCI ATA-100 card. I think I've figured out the problem everybody else had when they tried to run 133 FSB on this board, so I figure close to 1GHz and a gig of ram should make for a pretty sweet OS8 machine.

Anyway, this file is holding me up... Somebody help!

Thanks

-kh

 
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