imac boot failure

July 30, 2006 7:49 AM

I've been given a pretty old g3 iMac that boots up to "MacOS: Boot failure - unexpected value for MacOS ROM entry in segment table" and what appears to be a prompt. I know nothing about macs! Is this thing fixable? And if so, how?

Here's the whole thing:

MacOS: Boot failure! (0xFC3481F6)
MacOS: Boot failure - unexpected value for MacOS ROM entry in segment table

Apple iMac Open Firmware 3.0.f3 built on 12/02/98 at 10:25:41
Copyright 1994-1998 Apple Computer, Inc.
All Rights Reserved.
ok
0 > _

I don't have any of the original included software and I dunno if this is relevant, but it's green.

posted by mcsweetie to computers & internet (7 comments total)

I've never seen that particular error before, but it seems to imply that your boot ROM is corrupt. Fixing it is likely to be non-trivial.

If I'm wrong and you're lucky, a clean install of MacOS may be enough to fix it. Insert the CD and hold down the "C" key while it is booting to force a boot from the CD instead of the HD.
posted by Mwongozi at 8:12 AM on July 30, 2006

Yes, boot from a CD and install a fresh copy of MacOS.
posted by k8t at 8:36 AM on July 30, 2006

Some old G3s require a firmware upgrade to run OSX. Unfortunately you have to boot in order to do the firmware upgrade.
posted by Gungho at 9:43 AM on July 30, 2006

on preview...if you can boot an OS9 CD then you may find it possible to switch start up disks to the already installed OS9 if there is one.
posted by Gungho at 9:45 AM on July 30, 2006

If it's failing in Open Firmware, it's most likely that the "MacOS" ROM file on the hard drive does not support your model of iMac, most likely because it's too old. For example, if it's a dark green iMac from 1999 or later, it probably requires Mac OS 9 or later; trying to install Mac OS 8.5 on it (even in FireWire target disk mode) would leave it unbootable.

Find your iMac on this page, then find the minimum software version it requires, and get an installation CD for that version or later.

Actually, go for Mac OS 9.1 or later. Gungho is right - some older models require a firmware upgrade to run Mac OS X reliably, and the updater only runs under Mac OS 9.1 through 9.2.2. (Mac OS X's "Classic" environment won't do - the application needs direct hardware access to reflash the firmware, and Mac OS X doesn't allow ordinary applications to touch such things.) So try to install Mac OS 9.1 or later first, then upgrade to Mac OS X if you wish. I'll bet having the right "MacOS" ROM file on the hard drive (and the OS that goes with it) willf ix the problem.
posted by mdeatherage at 9:51 AM on July 30, 2006

Are you anywhere near an Apple store? Take it to the genius bar -- one guy there worked with me for a hour & a half trying to get a G3 iMac to allow an OS X install.

In that case, be prepared to buy a copy of OS X -- but I bet you could make a deal with the Genius "if you can get OS X to run on this machine, I will buy a copy of the OS."

In case of success, be prepared to max out the memory of the little beast.
posted by omnidrew at 7:26 PM on July 30, 2006

thanks guys! like I said, I don't have any of the original included software but I found a copy of MacOS 9.2 floating around on a torrent site but to install it I have to upgrade my firmware and the included upgrader keeps failing with the an error about the volume being locked. it appears as though there's no hard drive inside, or if there is, it's messed up somehow.
posted by mcsweetie at 11:36 AM on July 31, 2006