Mac OS 8.6 findings and ramblings

Discussion in 'PowerPC Macs' started by LightBulbFun, Dec 15, 2016.

  1. LightBulbFun, Dec 15, 2016
    Last edited: Apr 30, 2018

    LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #1
    so over the past couple weeks I have been playing with Mac OS 8.6 and i figured id just post my findings :)

    so to start the Mac OS 8.6 image im working with here is the as far as i know the last 8.6 image apple put out which was the image for the Sawtooth.

    now my goal with it was to try and get it running on computers that shipped with 9.x so with that said here is what I found out.

    The Mac OS ROM included with this image of 8.6 is different to later Mac OS ROMs in that it has a much more specific machine check that is run when loading from OF then later Mac OS ROMs (and in OS Xs BootX for that matter) see when the Mac OS ROM image or BootX is loaded in OF they run a small script at the start to check the "compatible" property in the Root of the open firmware device tree. now later Mac OS ROM images and BootX check just for the MacRISC, MacRISC2, MacRISC3 or MacRISC4 compatible property.

    but this image of Mac OS 8.6s ROM image has a much more specific check in that it has a list of compatible Model identifiers in the compatible check rather then just a Generic overall machine class compatible check. so instead of checking if Just MacRISC or MacRISC2 is there it has a list of model IDs it checks for. and the machine IDs it checks for before counting to load if found or aborting if not found are. iMac,1 PowerMac1,1 PowerBook1,1 PowerMac2,1 PowerMac3,1 PowerBook2,1.

    so on any of the machines the Sawtooth image of 8.6 would boot up fine. but if say you tried to boot it on a PowerBook G3 Pismo it would abort as it would go to check the compatible listing in OF and pull up PowerBook3,1 and abort as thats not in the compatible list. now I had to get around this the easiest way to do this was simply to change the PowerBook3,1 listing in the compatible property in OF to PoweBook2,1 for that boot session (it is possible to make it persistent but thats for another time)

    so I did that and it low and behold Mac OS 8.6 started to boot on the Pismo however near the end of booting from the installer CD the machine would just turn off without warning so I took the HDD and manually installed 8.6 to the HDD and re did the above steps this time booting from HDD and it booted all the way to the desktop. I got 8.6 running on an unsupported and newer computer then it self :)

    a couple quirks with it is it does not detect the battery (tho it runs off battery fine) and the Rage 128 drivers dont load (this one is probably solvable by installing newer ATI drivers) and finally another interesting thing I noticed was with a normal 8.6 install 8.6 does not recognise a 7410 CPU Properly but this sawtooth image on my Pismo has no problems knowing what to call the 7410 that I have fitted. (which is interesting as the 7410 had not yet come out when the Sawtooth went on sale but i would not be surprised if apple was already playing with engineering samples or the like)

    I hope this all makes sense (im not very good at making proper forum posts :p ) its not meant to be a guide or anything just a post on my findings and that it is possible to boot Mac OS 8.6 on unsupported/newer Macs :) (I did try this on a 800Mhz Snow iBook G3 and it did not get very far before hanging sadly.) and I may go into greater detail in what i did at a later point. :)


    [​IMG]
     
  2. AphoticD, Aug 22, 2017
    Last edited: Aug 22, 2017

    AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #2
    Hey LightBulbFun, great work here. I think you may have the world's only OS 8.6 booting Pismo!

    I recently acquired a gorgeous Pismo G3 400Mhz. I used spare parts from my upgraded TiBook to bring the specs up a little to 320MB of RAM and a 40GB 4200rpm HDD. (The PC133 SODIMM worked fine in a PC100 slot).

    I have been trying to get Mac OS 8.6 to boot as per your notes. I took a slightly different route, but still can't get anywhere;

    1. Prepared a clean "Universal" install of Mac OS 8.5 in SheepShaver.
    2. Upgraded the install to 8.6.
    3. Used Disk Utility in Tiger to "Restore" the Sheepshaver disk image onto a real partition on the Pismo's HDD.
    4. Blessed the System Folder on the new Mac OS 8.6 partition (sudo bless -folder9 /Volumes/Mac\ OS\ 8/System\ Folder)
    5. Selected "Mac OS 8.6" from Startup Disk System Preferences in Tiger.
    6. Rebooted into Open Firmware (Cmd-Opt-O-F)
    7. Used these OF commands to spoof the model identifier:
    Code:
    dev /
    .properties
    " PowerBook2,1" encode-string " model" property
    " PowerBook2,1" encode-string " MacRISC2" encode-string encode+ " MacRISC" encode-string encode+ " Power Macintosh" encode-string encode+ " compatible" property
    mac-boot
    
    Unfortunately, each time it fails to even attempt to boot into 8.6 and shows just the flashing system folder for a few seconds before launching into a Tiger boot.

    I have also tried booting into Mac OS 9.2.2, moving the Finder out of the 8.6 System Folder, putting it back in (to "re-bless") and then selecting 8.6 from the Startup Disk Control Panel, before restarting and re-applying the OF command.

    I think your Mac OS ROM file from the Sawtooth could make all the difference here. Are you able to compress and upload a copy?

    Thanks,
    -AphoticD
    --- Post Merged, Aug 22, 2017 ---
    I am downloading an image of the Sawtooth restore disc named sawtooth_8.6_restore&Install.zip.

    This may do the trick...
     
  3. LightBulbFun, Aug 22, 2017
    Last edited: Apr 30, 2018

    LightBulbFun thread starter macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #3
    your OF commands like good, (I would recommend doing boot cd:,\\:tbxi instead of mac-boot. also keep in mind the OF changes are volatile ie they will reset once you reboot/reset the machine)

    but you do need a Sawtooth 8.6 install, as thats the latest 8.6 image and contains the most up to date uninorth drivers. the install CD image i found on the internet is called sawtooth_8.6_restore&Install.zip

    fun fact this also works on MDDs :), one thing I have noticed, is the GPU you have installed in the machine can prevent the Mac OS ROM from loading properly. and I had to use the ATA33 keylargo bus (I cant remember if the ATA66 Keylargo bus worked) (I Know the ATA100 bus hanging off the U2 controller does not work in 8.6)
    for an MDD, substitute PowerBook2,1 for PowerMac3,1 (I suspect 8.6 could also be made to work on GigE DA and QS G4s but i sadly dont own any of those)

    [​IMG]
     
  4. AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #4
    Okay, I got it!

    1. Downloaded and burned the Sawtooth G4 8.6 Restore & Install CD.
    2. Used the Software Restore application on the CD while running under Mac OS 9 to copy the G4's restore image onto the Pismo's OS 8 partition.
    3. Set the newly restored Mac OS 8.6 as the active Startup Disk.
    4. Rebooted and used the OF commands to spoof just the "compatible" property to PowerBook1,1 (PowerBook2,1 refused to work for me)
    Code:
    dev /
    " PowerBook1,1" encode-string " compatible" property
    mac-boot
    
    5. Mac OS 8.6 boots with a happy Mac and a desktop!
    6. I copied all of the ATI and FireWire extensions from Mac OS 9.2.2 across to the 8.6 System Folder and rebooted again (applying the OF commands on each boot). With these extensions, we have full graphics acceleration and FireWire support. This part was easier than I expected it would be.


    Picture.jpg


    It's worth noting that although this is fun, it has caused the Pismo to run _very_ hot. I can see that the power saving / processor cycling software is not functioning properly regardless of my settings in Energy Saver.

    I'll need to keep playing around with it, but I think power management is going to be at the (nano) kernel / ROM level and not something as simple as updating a control panel or extension file.

    I haven't changed the thermal paste or pads yet, and the cooling fan doesn't seem to ever come on (maybe it's broken?). I shouldn't have been surprised as the room was starting to warm up as well, but all of the playing around started causing signs of the old Pismo overheating. First the memory test began to fail on each boot and then there were graphical glitches. I shut it down for 10 minutes, rebooted into Mac OS 9 and found everything was running cool again.

    While both operating systems have Energy Saver set to "Better Conservation", the idle CPU temps as shown in Gauge PRO are;

    Mac OS 9.2.2 CPU when idle 30°C
    Mac OS 8.6 CPU when idle 46°C (Too high for a G3!)

    I'm wondering if the PowerBook1,1 "compatible" property could be preventing the power management from running properly... @LightBulbFun, does your Pismo run notably hotter in 8.6?
     
  5. LightBulbFun, Aug 22, 2017
    Last edited: Aug 22, 2017

    LightBulbFun thread starter macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #5
    Very cool to see you got it working too :) (I did not even know firewire did not work in 8.6, I never tested it in Mac OS 8.6 LOL)

    I highly recommend you try and get PowerBook2,1 working, as that is the closest matching mac to a Pismo, (PowerBook2,1 and PowerBook3,1 are both Uninorth 1, Keylargo machines, where as PowerBook1,1 is a Gossamer/Heathrow machine) what sort of issues are you getting when you try PowerBook2,1?

    in regards to overheating, I have not noticed any issues in that regard with my Pismo, and I Have run a Lot of OSes on my Pismo from Mac OS 8.6 to Mac OS X 10.5.8 :) and thats on top of the fact I have a 600Mhz 7410 soldered to my CPU Card (see here https://forums.macrumors.com/threads/making-a-g4-pismo-upgrade-at-home.2019269/ :D ), and im still running with stock cooling(save for removal of the old thermal sheet on the heatsink and an application of fresh thermal paste on the CPU). it takes a LOT of intensive work to get the Pismos system fan to turn on, if I, say play an intensive game of Quake 3 after like 20-30 minutes the little CPU fan will kick in and thats with a 600Mhz G4. its been rock solid stable for me :) (the pismo that is, I have not extensively used 8.6 on it)

    (Speaking of I really need to order more 512MB PC133 SODIMMs my only one is currently sitting in a iBook G3 clamshell, its on the list of things i need that i never get round to ordering like some more solder wick so i can commence on the iBook G3 CPU swap :D)

    what kind of CPU heatsink does your Pismo use? I have noticed that there are 2 types... I wonder if one is better then the other (mine is the type where all of it shiny, but theres another one where the main heatsink hanging off the heat pipe is a matt gray colour)

    BTW I cant help but notice that your missing L2 cache in system profiler and that only 160MB of RAM is showing? do you see L2 cache when booted into Mac OS 9.2.2?/OS X, if not, do you get a pop up in Classic Mac OS mention Cache failure/does diagnostics in OS Xs system profiler mention cache failure? it might be related to your overheating issues, Also is your Boot ROM fully up to date? theres a surprising amount of machines where this is not the case, I highly recommend you update to the latest which would be 4.1.8f5 for the Pismo IIRC

    in theory you should be able to edit the Mac OS ROM it self and avoid having to do any sort of OF hackery, but I have not been able to get this to work (following the guide for hacking the Mac OS 9.2.2 ROM, even replacing abort with clear it still halts on a checksum error for me)

    I also should mention for the MDD to work in 8.6, Much like booting Mac OS 9.2.2 on a 7447/A/B or 7448 you have to fake the CPU PVR (processor version register) to one that was around when that OS was put out so in the case of Mac OS 8.6 I changed the 7455Bs PVR in OF to that of a 7400, this once again is volatile
     
  6. AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #6
    Thanks! I made some further progress this morning.

    Initially, I would get a message during boot saying that the software installation needs to be updated and it gave me a "Restart" option. I have since successfully re-run the PowerBook2,1 OF commands and it is booting OK. (Perhaps it was a first-boot thing).

    IMG_2123.jpg

    I can confirm that Mac OS 8.6 is definitely causing thermal issues. On cold boot, Mac OS 9 gave me a temp of 22°C, I then set the Mac OS 8.6 as the Startup Disk, rebooted, entered the OF commands and booted to the 8.6 Desktop. Checking Gauge PRO showed a massive jump to 38°C within only a few minutes. I let it sit for a few minutes to see if it might drop, but it held it's place. Energy Saver settings are at Conservative and Processor Cycling is enabled in the control panel.

    IMG_2121.jpg
    (Mac OS 9.2.2 running at 22°C after a cold start).

    IMG_2124.jpg
    (Mac OS 8.6 after a reboot, hitting 38°C).

    On next reboot (only a few minutes later), Mac OS 9 reported memory test failure at startup and the L2 cache was disabled.

    I shut it down, let it cool, pulled it apart and re-pasted the CPU with silver and a new sheet of magic 2mm silicone thermal padding between the heatsink and the aluminum cage.

    A reboot into 9.2.2 after the re-paste showed 22°C again. I am hesitant to boot back into 8.6 as I don't want to fry my new baby!

    It's the shiny aluminum type.
    IMG_2120.jpg


    Yes, the low RAM and missing L2 cache are a direct result of overheating while running OS 8.6. After letting it cool off for a few minutes seems to resolve it, but as I mentioned, 8.6 keeps causing it to overheat.

    The Boot ROM is 4.1.8f5

    I think I might just leave 8.6 alone now... I don't want to fry the little '750. I will however, use the partition to play around with Rhapsody DR2 and some versions of Kodiak. 10.0 DP2 looks really cool being a unique design hybrid of 9/X.
     
  7. LightBulbFun thread starter macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #7
    its been a while (I got a bit side tracked with other things)

    but a while ago I managed to finally hack the Mac OS ROM from the 8.6 Sawtooth image so it would boot on unsupported machines without any OF fiddling :) I more or less applied the patches the User iMacC2D used on the Mac OS 9 ROM, to the Mac OS 8.6 ROM. :) (sadly it seems he has left MR and also removed all of his content from his thread on getting 9.2.2 booting on unsupported macs)

    note tho that if you have a 7450 or newer you will still have to Fake the CPU PVR in OF to that of a Rev 2.7 7400.

    to use it just image the Sawtooth install to a HDD and replace the "Mac OS ROM" file with this one :)

    so far the machines iv tested it on:

    Pismo will Boot OOB

    Dual 1.42 MDD FW800 with FW400 BootROM will boot as long as you Fake the PVR and use the Key-largo ATA bus

    Dual 1.42Ghz MDD FW800 with stock boot ROM. WONT boot this ROM sadly. (even with a Rage 128 PCI) still need to look into this some more.

    and my SnowBooks (PowerBook4,1 and PowerBook4,3) and iMac G3 PowerMac2,2 wont boot the 8.6 ROM either strangely... im not entirely sure why these 2 wont boot seeing as the Pismo does, and the PowerMac2,1 is officially supported by 8.6

    I have noticed that certain video cards can stop the Mac OS 8.6 ROM from booting. so that might be something to look into

    I suspect GigE Cubes DAs and Quicksilvers would be able to Boot Mac OS 8.6 with my Hacked ROM :) (but sadly I dont own any of those machines to test the ROM on)

    https://mega.nz/#!VUgFAKZR!xXTi_4BK2wJHU8QYCoqyNIjq2aZFPFnM7B4JlmY1lRk

    (I also formatted the OP a bit so its not one massive wall of text. :D )
     
  8. AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #8
    Nice work man! I'll have to try it out on the Pismo and the PowerBook3,2 (Mercury).
     

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7 December 15, 2016