Member Avatar for mutley3legs

My husband has just bought an iMac G3 333mgz, with a broken CD Rom Drive.
We know that to load Mac OS with an internal drive, you press the C key on start up, but how do we go about it from an external USB drive? :o

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For an iMac G3 with a dead internal CD‑ROM, the most reliable routes are FireWire-based installs or using another Mac as a donor — USB optical drives from that era are often not recognized as bootable. Building on and , here are practical, low-risk options and what to watch for.

Create a bootable FireWire disk from a working Mac

  • On a working Mac with an optical drive, use Disk Utility to create a disk image of the installer CD (or set the CD as the source).
  • Attach an external FireWire hard disk, format it as Mac OS Extended (HFS+) and set the partition scheme to Apple Partition Map (APM — critical for PowerPC Macs).
  • Use Disk Utility’s Restore function to copy the CD image to the FireWire drive. Once finished the FireWire disk will behave like an installer disc and the G3 can use it to install or run the installer.

Use another Mac to install onto the G3’s drive

  • With a FireWire cable and a second Mac you can make the G3’s internal disk appear to the working Mac (the donor Mac can then run the installer and target the G3’s drive). Before installing, verify the G3’s internal drive is formatted as HFS+ with an Apple Partition Map. This avoids compatibility problems during installation.

Other practical choices and troubleshooting

  • If the G3 won’t see the external device, confirm it’s a FireWire device, the drive is powered, and the partition map is APM (GUID won’t work on PPC).
  • Retail vs. machine-specific restore discs: use an installer that supports that iMac model.
  • If those options aren’t possible, swapping the internal optical drive or temporarily installing the G3’s hard disk in another machine (or with an ATA adapter) are realistic fallback solutions.

Always back up any data before repartitioning or reinstalling.

Recommended Answers

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Member Avatar for Kezz

Try holding the option key down during startup, which gives you a chance to select any available system disk to start up from.

Member Avatar for John A

If you have a spare Mac, you can boot from it using Target Disk Mode. Shut down the Mac that you want to boot, and connect a Firewire cable to it. Then, while starting it, hold down the T key.

That is, assuming that you have a spare Mac :D.

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