open firmware’s default catch

i was upgrading a friend’s iMac G3* to Mac OS X 10.3.9 today. after we rebooted, he was stuck in open firmware. after i typed mac-boot at the prompt, it said default catch and refused to proceed any further.

the usual trick of

did not help.

what did fix the problem was booting off the mac os x installer CD, selecting his hard drive in the startup disk application and restarting the machine.

* with a 20 GB hard drive, partitioned in to 8 and 12 GB partitions, as required.

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  1. Macintosh starts up to Open Firmware or gray screen after upgrading hard drive
    If you upgrade your Macintosh computer from its original hard drive to a new hard drive that is larger than 8 GB, you may see some odd symptoms, such as one of these:

    When the computer starts up, it displays a gray screen. The desktop never appears.

    When the computer starts up, it shows a white screen, with text that includes the phrases, “Open Firmware” and “default catch”.

    When the computer starts up, you may see an alert message such as “unimplemented trap” or “segment loader error”.

    When you try to install Mac OS X on the computer, the hard disk is dim and can’t be selected in the installer.

    This only happens with certain Macintosh computers that originally had a hard drive smaller than 8 GB, and that have now been upgraded with a hard drive larger than 8 GB. These computers include:
    iMac 233 MHz

    iMac 266 MHz

    iMac 333 MHz

    Power Macintosh G3 Desktop

    Power Macintosh G3 Mini Tower

    Power Macintosh G3 All-In-One


    iBook (FireWire)

    PowerBook G3 Series

    If you have just upgraded the hard drive on one of the computers listed above and you see this issue occurring, here’s how to get everything running smoothly again:

    Back up all your data. (This is a good thing to do regularly, not just now!)

    Start up from your Mac OS installation or restore disc.

    Use Drive Setup (in Mac OS 8 or 9) or Disk Utility (Mac OS X) to partition the drive. Make the first partition smaller than 8 GB, and any other partitions can be any size you want.

    Install the Mac OS in the first drive partition.

  2. Was trying to install OS X 10.4 tiger on my 15″ flat panel imac and was getting these same errors. I then tried the above suggestion and it solved the problem. Thanks.

  3. I had the same problem, but not related to an update. I opened the machine and held down that little button by the battery…I can’t remember what it’s called, but it’s an acronym. I held that little sucker down for a good ten seconds, and low and behold, what to my wondering eyes did appear, but an O-S-X and a gernally wonderful overall startup experience.

  4. yo paul … devon from the animators here … trying to fix our studio machine and came across your site! go figure. you’ve got the most popular default catch in town.

    hope to see you soon …

  5. Huge help in an emergency! Pulled the battery and held the button and it worked like a charm. Got that big beautiful gray apple up on an old B&W 450 G3. Thanks for the info.

  6. Hoo Ray. Never seen this before DEFAULT CATCH! and hub errorff939xxxxetc.

    I thought the Blue G4 (running 9.1) was headed to the recycle dumpster after too many years for faithful service. Pulled the battery and pushed the silver button just north of the positive terminal (never knew it was there until reading Raymond above) and bam, desktop. I think I will back up now. thanks Raymond and thread. I did not reinstall system or partition a disk. I just pulled the battery and pushed the button.

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