Roll your own 7448?

Discussion in 'PowerPC Macs' started by DearthnVader, Apr 26, 2018.

  1. DearthnVader macrumors 6502a

    DearthnVader

    Joined:
    Dec 17, 2015
    Location:
    Red Springs, NC
    #1
    I have a few Macs with 7447's and I'm interested in the work being done to bake a 7448 onto these systems.

    As far as I'm aware the 7448 requires a Firmware patch to the Boot ROM.

    Just wondering if anyone has decoded what the patch does?

    I have a Quicksliver that I could run the Sonnet patch on and try to image the boot rom and run a hex compare to try and find exactly what is being patched, if the system can still boot with the 7455's in it after the patch is applied?
     
  2. mrkapqa macrumors member

    Joined:
    Jan 7, 2012
    Location:
    Italy, Bolzano/Bozen
    #2
    i'd love to upgrade a MacMini to such a CPU, but where could one buy such?

    And then, upgrade?
     
  3. LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #3
    if you download the sonnet firmware patcher from the sonnet website there is a resource file in there that contains the patches for a variety of machines (including a 7457 patch for the GigE TiBook...)

    but its worth noting that I dont know how sonnets firmware patch would do with a 7448 as Sonnet never released any 7448 based products.

    in regards to patching the boot rom and checking against an un-patched one, you can in most cases patch the Firmware and still run with the stock CPU, but I have sadly not found a way to dump (and flash back) a PowerPC macs BootROM without de-soldering the EEPROM and reading it off externally, it seems like flashrom on linux would be a good bet but it does not support PowerPC properly sadly (it does work well on intel macs tho :) https://forums.macrumors.com/threads/updating-a-mac-pro-s-cpu-microcode.2114187/ ) there where some patches put forward in 2011 for PPC FlashRom support but it seems like those never got anywhere. https://mail.coreboot.org/pipermail/flashrom/2011-August/007565.html

    I would love to get both a 7447/A and 7448 based CPU upgrade card to play around with all the diffrent firmware patches etc and figure out exactly how everything works exactly. but thats much easier said then done (finding any sort of G4 CPU upgrade card is quite hard and pricey these days let alone a 7448 one)
     
  4. AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #4
    Not exactly a 7448 upgrade, but I spotted an OWC Mercury Extreme (2nd gen) G4 1.4Ghz (7455) with 2MB L3 cache on the 'bay shipping out of Poland;
    https://www.ebay.com.au/itm/MAC-SG4TS-B4-COOLER-FAN-2-PIN-POWER-MAC-G4/173285660149?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
    (not my listing)

    The seller has incorrectly identified it as a "2-pin Cooler Fan".

    I would buy it for my Sawtooth, except for the fact that shipping to Australia is marked as AU$122 for some reason... Maybe someone in Eu/UK might grab it?
     
  5. LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #5

    Cool find, Im pretty sure looking at its design that its a re-badged/badge engineered sonnet CPU card which means it should be possible to fudge it into a G4 cube :) sadly the seller does not ship to the UK, but its not too much of a loss for me as I do have a lead on a 7455B based upgrade for my Sawtooth :)
     
  6. AphoticD macrumors 68000

    AphoticD

    Joined:
    Feb 17, 2017
    Location:
    Australia
    #6
    They offer shipping to Australia but not to the UK? How strange.

    It does look the same as the Sonnet upgrades (and uses similar model codes). OWC have simply slapped a shiny golden heatsink and their logo on it. There are quite a few positive reviews of this card on xlr8yourmac.com. The jumper switches on the side appear to allow it to OC up to 1533 / 1600mhz (depending on bus speed).

    How does the 7455B compare to the 7455? I can only imagine it ran cooler as the 7455 generates quite a lot of heat. It looks like the final revision Dual 1.25Ghz MDD had the 'B' chip, were there any other Macs?
     
  7. LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #7
    interesting find on the 2 dip switches there, Sonnet cards dont have any way for the user to adjust the CPU speed, so the OWC CPU is diffrent from Sonnet ones... but it does still look quite similar to a sonnet CPU, it would be fun to physically compare a 1.4Ghz sonnet and a 1.4Ghz OWC CPU upgrade :)

    as for the 7455 vs 7455A vs 7455B they are more or less identical but each one clocks faster then the last :)
     
  8. mrkapqa macrumors member

    Joined:
    Jan 7, 2012
    Location:
    Italy, Bolzano/Bozen
    #9
  9. DearthnVader thread starter macrumors 6502a

    DearthnVader

    Joined:
    Dec 17, 2015
    Location:
    Red Springs, NC
    #10
    Thanks LBF,

    I thought Sonnet did release a 7448 CPU, but that's what I get for thinking.

    As to dumping the Boot ROM, some info here:

    http://macos9lives.com/smforum/index.php/topic,4295.msg29654.html#msg29654

    Also, I could be wrong, but I think people were able to update/downgrade the Boot ROM for the FW800 MDD, and I don't recall any FW updaters for that Mac. So you may want to check:

    http://macos9lives.com/smforum/index.php/topic,762.0.html

    I was thinking that all new world macs had a programmer mode, and what was required to update the FW was to somehow "bless" the firmware file you wanted to use as and update, and evoke the programmers mode , but again I could be wrong.
     
  10. DearthnVader, Apr 27, 2018
    Last edited: Apr 27, 2018

    DearthnVader thread starter macrumors 6502a

    DearthnVader

    Joined:
    Dec 17, 2015
    Location:
    Red Springs, NC
    #11
    Ok, I was wrong, there was a FW update for the MDD FW400.

    https://support.apple.com/kb/dl1179?locale=en_US

    You can extract the updater with Pacifist.

    If you are brave:

    Code:
    dev /
    " PowerMac3,6" encode-string " model" property
    mac-boot
    I'm not that brave, I confirmed the FW Update would run, but I didn't hit the restart button, because I didn't feel like frying the logic board on any of my Macs.

    I have no clue if it would update any NW mac, or if each one needs specific logic.

    If you show the package contents, and look within, you'll see the firmware file, you maybe able to just replace the file with a valid FW image you want to flash.

    I assume it will work, as the 3rd party FW updates were AIO, but I've fried a few PC motherboards doing these sort of ill advised things.

    Warning: Don't try this unless you are willing to replace your logicboard. I take no responsibility for what may happen if anyone tries. This info is meant for advanced computer hackers only, and may fry your computer beyond repair, burn your house down, kick your dog, and knock up your teen aged daughters.
     
  11. LightBulbFun macrumors 68000

    LightBulbFun

    Joined:
    Nov 17, 2013
    Location:
    London UK
    #12
    Yeah I have seen most of what you have posted already :) I have a FW800 Mobo here that I downgraded to the FW400 BootROM back in the day, but I wish to flash it back to FW800 ROM but sadly Apple never issued a FW update for the FW800 machines, so I would have to flash the entire BootROM from another FW800, but to do that I need to be able to Dump the BootROM whole, from one of my FW800 MDDs then flash it, and sadly I dont think theres any way to do that currently...

    the Firmware updates that PowerPC macs use, they are not exactly just the Macs firmware they also contain an OpenFirmware script to actually flash them self. all the BootROM updater app in OS 9/OS X does is move the BootROM update file somewhere and bless it, when you Reboot into programmers mode the Mac simple just boots from the file, like how it boots from BootX for example. AFAIK you cant use a full BootROM Dump from another mac and Flash it in the same way a BootROM update flashes it self. you would have to use some proper EEPROM programmer (and likewise you cant take an Apple BootROM update and flash it via it an EEPROM programmer)

    also I REALLY WOULD NOT RECOMMEND FLASHING THE MDD FW UPDATE TO ANY MAC THATS NOT AN MDD! YOU WILL BRICK A MACHINE! (I really would not of posted what you did, in the first place... too much of a risk of someone bricking a machine...)
     

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