Converting a MBR-partitioned drive to APM for use on PPC G4

Discussion in 'PowerPC Macs' started by markux, Mar 5, 2009.

  1. markux macrumors newbie

    Mar 5, 2009
    I am trying to replace the hard drive on an old 450 MHz PowerMac G4 (AGP Graphics) which I bought years ago off eBay for my young child to play with. Now I'd like to use this Mac again as a sandbox for learning how to integrate OSX into Windows dominated corporate networks.

    The original internal drive is a 27 GB IDE Seagate Barracuda, and I'd like to install an available 80 GB Seagate drive, which at some point had been partitioned on an Intel PC (running Windows or Linux).

    At first I wasn't aware that an incompatible partitioning scheme on PPC Macs might prevent this. I became suspicious only after numerous seemingly successful installs of OSX Tiger (on any 80 GB drive) the Mac would not recognize the drive (not even acknowledge its presence) after the subsequent reboot.

    This was the case when attaching the drive internally. At one point I managed to execute a boot command (forgot which one) that took me to a prompt where I could select the external drive as the boot drive. However, this only worked when the drive was in an externall Firewire enclosure, AND only with the original drive still attached internally, AND I had to perform this manually at each reboot.

    Finally my original drive died. Now I need to find a way to boot from the replacement drive installed internally. (Having a dozen barely used older drives available I'm too cheap to go out and buy a brand new one, especially since there's no guarantee that a new drive isn't already partitioned - and these days it's hard to find anything smaller than 160 GB anyway - the G4 only supports up to 128 GB.)

    After much research I learned that the need for the proprietary Apple Partitioning Scheme (APS) on the PPC platform must be the issue. While the newer Intel-based Macs appear to come with an updated Disk Utility which provides the option to choose the partitioning method (between APS, GUID, and MBR) my original Tiger DVD does not have that option. Since this is my only Mac, and I paid dearly for the OSX Tiger upgrade a few years ago (and this Mac is only supposed to be a test environment) I am not inclined to buy another OSX disk/license at this time.

    Despite scouring all the Mac forums I have not identified a practical way to get a bootable APM partition onto a hard drive once it's been spoiled with another partitioning scheme. Multiple seemingly successful OSX installs (during which I created brand new volumes with Disk Utility's Partitioning feature) end up with failure to recognize the drive upon reboot. I tried this with multiple drives from different manufacturers, although all of those drives at some point had Windows or Linux on them.
    Any ideas on how to wipe a MBR-partitioned drive totally clean and force APM upon it would be greatly appreciated?
    Am I possibly missing something else here?

  2. TDM21 macrumors 6502a


    Jul 7, 2004
    The easiest way I can think of fixing the partition table without a Leopard DVD would be to run a Linux LiveCD that includes Gparted. I know Ubuntu has it and is probably the easiest to use. Head to to grab a Desktop CD for PowerPC. Release 7.10 should work for what you need. Just stay away from the 8.10 release because it won't boot without some special commands.

    Once you've booted to the desktop, go up to System > Administration > Gnome Partition Editor. In Gparted there will be a drop down list on the right that will allow you to select your hard drive. With it selected go to the Device Menu and click on "Create Partition Table..." (older versions of Gparted called it "Set Disklabel." Regardless it should do the same thing). If you expand the Advanced menu, you will see a drop down list for all the different partition tables Gparted supports. Choose "mac" and click the Create Button. That should erase all the information off the drive and create an Apple Partition Map. You can then try rebooting your PowerMac from the Tiger DVD and check to see if Disk Utility will allow you to add an HFS+ partition.
  3. markux thread starter macrumors newbie

    Mar 5, 2009
    Great idea, unfortunately it didn't work

    Thanks, TDM21!
    It took me a while to get the Ubunto Live-CD to boot on that machine. GPARTED did in fact create a new partition scheme, using the 'mac' option.
    However, after installing Tiger from the Tiger DVD the hard drive would still not be recognized. Booting with the Alt key takes me to the boot disk selector, which unfortunately shows blank. I'm about to give up and strip this thing to sell the good parts individually. Maybe the proceeds will pay toward a newer, better supported Apple model ;-)

  4. canonballs macrumors member

    Mar 8, 2009
    That's the alt/option key

    Did you try erase or secure-erase? If that does not help, you could try screwing the file system up (assuming you have access to a booting computer) — on a Mac you could use something like iBored, so that the Mac does not recognize the filesystem and is forced to format the drive afresh.
  5. sushi Moderator emeritus


    Jul 19, 2002
    First, I am not sure why you cannot connect the 80GB HD to your G4, then boot from the Tiger installation DVD and then run Disk Utilities to partition and format your HD, then install Tiger and have it boot into Tiger.

    Normally, this is easy to do with Tiger and Disk Utilities as long as you have the full version of the Tiger installation DVD and not the inbox upgrade one.

    If you have the full Tiger installation DVD, and cannot boot to it and use Disk Utilities to partition and format the HD and install Tiger, there is one option that I can think of if you have a PC handy.

    You can use KillDisk and wipe the drive using a PC.

    Download the free version of KillDisk. Create a boot floppy or boot CD.

    Then disconnect your internal HD in the PC and connect the HD that you want to use in the G4. Then boot running KillDisk and erase the HD. It erases everything including the MBR and PT.

    Then connect the HD back to the G4 and then boot from the Tiger install DVD, run Disk Utilities and then partition, format the HD and install Tiger.

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