Comments on: Reinstall Mac OS on G3 iMac after installing Linux?

Question: Reinstall Mac OS on G3 iMac after installing Linux?

AmbroseChapel — Mon, 19 Mar 2007 12:50:24 -0800

Reinstall Mac OS on G3 iMac after installing Linux?

I have an old 333MHz G3 iMac (the first generation of the "fruity colours" model).

I installed YellowDog Linux on it. No dual-boot, just linux.

Now I'd like to return it to use with Mac OS X or even OS 9 and I can't seem to do so.

I can boot from the installer disks OK, but the OS X installer disk thinks for a while then gives me a forbidden/ghostbusters symbol, and the OS 9 installer just gives me a mouse and a blank screen.

Presumably they don't recognise the existence of the HD because it's not formatted the right way? So what can I do to reformat the disk in HFS, or whatever I would need for the installers to acknowledge the existence of that enormous 6GB drive?

By: doctor_negative

doctor_negative — Mon, 19 Mar 2007 13:00:23 -0800

After you boot from the CD, Disk Utility is available in one of the menus. Switch to Disk Uitlity to reformat, then install from the CD.

By: pmbuko

pmbuko — Mon, 19 Mar 2007 13:02:24 -0800

Boot from the OS X install disc. When the installer appears, go to the Utilities menu and choose Disk Utility. You should be able to reformat your drive from there, then return to the installer (by quitting Disk Utility) and continue with the OS installation.

By: AmbroseChapel

AmbroseChapel — Mon, 19 Mar 2007 14:06:17 -0800

I obviously haven't made myself clear.

I can boot from the installer CD in the sense that it doesn't boot into linux, but all I see is what I described above. If I had the OS installer I'd be fine.

With the OS X disk I see a grey screen and the "forbidden" symbol, that's it. No installer, no apps, no menus, nothing to click on.

By: WCityMike

WCityMike — Mon, 19 Mar 2007 15:26:38 -0800

My thought is that perhaps it's trying the hard disk even with the CD-ROM in the drive. Try holding down the 'C' key for a very long length of time (>1 min.); does the installer eventually appear?

By: wearyaswater

wearyaswater — Mon, 19 Mar 2007 15:30:31 -0800

This same thing happened to me, except with a Powerbook. I looked and looked for a fix, but I couldn't find one, and people kept assuming that I didn't know how to correctly boot from the installer CD. The whole thing was frustrating as hell. I eventually caved in and just bought a new hard drive.

By: AmbroseChapel

AmbroseChapel — Mon, 19 Mar 2007 16:14:51 -0800

>My thought is that perhaps it's trying the hard disk even with the CD-ROM in the drive.

Definitely not, I'm afraid. I'm holding "C" for long enough, it's making CD noises, not HD noises, plus it's unmistakably a Mac OS X installer which starts, but it's hanging and showing that "forbidden" sign after a few seconds.

By: Malor

Malor — Mon, 19 Mar 2007 16:24:23 -0800

One thing you can try would be to wipe the drive from within Linux; this will erase EVERYTHING.

Boot up Linux, open a terminal, and type 'mount' by itself, and hit enter. You'll get a list of mounted partitions, which will tell you what your devices are. (I've never used Linux on a G4, so I'm not sure how the devices come out.) An example from an x86 box:

/dev/sda5 on / type ext3 (rw,errors=remount-ro)

You'll probably see a lot of lines, but you want the one that says "on /" in the middle. That's your root partition and is most likely your boot disk.

In my line above, the /dev/sda5 partition is mounted as /; that's the "5" partition on the "sda" device. sda is the whole disk; 5 is one of the partitions.

What you want to do is wipe out your equivalent of sda; it could be hda, or it could be something else. (I'd guess it's most likely to be hda.)

Once you know your target device, type:

sudo dd if=/dev/zero of=/dev/sda bs=512

and hit enter. Substitute your device for sda, of course.

Warning: this will destroy all data on the drive.

Let that run a minute or so, and then just do a hard power off on the machine; there's no point in trying to shut down, as you've just blown away the entire drive. The machine will crash very shortly anyway.

That should wipe out all partitioning information from the drive and should let you reformat it with the Mac utilities. I can't absolutely promise, because Mac G4 hardware is strange to me, but I'm pretty sure it'll work.

By: Malor

Malor — Mon, 19 Mar 2007 16:25:31 -0800

(you may have to type your password with sudo, btw. that's normal.)

By: AmbroseChapel

AmbroseChapel — Mon, 19 Mar 2007 16:34:43 -0800

Thanks major, I'll try that. I'm happy to lose all the data, but cheers for the warnings.

It's G3, not G4 hardware, by the way, not sure what you meant by that last sentence!

By: Malor

Malor — Mon, 19 Mar 2007 16:59:36 -0800

G3/G4... pretty much the same, as far as I know. The reason I'm not absolutely positive it will work is because I'm not sure that Macs store all their partition information on the drive. I think they do, but I also know that the Open Firmware (the Mac BIOS equivalent) stores information about partitions for booting. It's possible that a drive wipe alone might not be enough.

If it's not, and you still can't boot, I'd try zapping the PRAM... you can do that with a particular key sequence. The sequence is command-option-p-r, all held at the same time, when you first power the machine on.

If a wipe and a PRAM zap don't work, I'm out of ideas. :)

By: timelord

timelord — Mon, 19 Mar 2007 19:00:06 -0800

You should be able to configure your bootloader to present a menu at startup, including the option to boot from a cd. Since you're using a G3 imac, I'm going to assume that the default bootloader is yaboot.

The easiest way to set this up would be:
1) open up the file /etc/yaboot.conf in your favorite editor* as root

be sure to do this as root

2) Somewhere at the end of the file, if it's not already there, add the line:

enablecdboot

3)Make sure that somewhere in the file you have 2 lines similar to this:

delay=X

timeout=Y

Where X and Y represent number of seconds. By default it's usually 5 for delay, and 30 for timeout.
4)In a console/terminal window type

su
ybin -v

It should ask for your password.

5) Reboot and you should get a menu. Type "c" to boot from CD.

*The simplest editor to use would be pico.
To open the correct file type

su
pico -w /etc/yaboot.conf

By: timelord

timelord — Mon, 19 Mar 2007 19:04:57 -0800

Alternatively you could boot into open firmware. This article includes instructions. It's actually even simpler than the method I described above because it only takes about 2 steps.

By: AmbroseChapel

AmbroseChapel — Mon, 19 Mar 2007 20:29:27 -0800

Malor, you're the man. It's sorted.

timelord, I'm sure that's useful advice for someone who couldn't get the "boot from cd" part to work...

By: Malor

Malor — Tue, 20 Mar 2007 02:33:09 -0800

Ambrose, if you check back... just out of interest, what was the device on the G4?

By: smallerdemon

smallerdemon — Tue, 20 Mar 2007 14:20:41 -0800

Unmentioned in your initial question is what flavor of Mac OS X boot CD you have. I am assuming you have Panther, since, for one thing, it's a CD and the 333MHz iMac never came with a DVD drive. You might have some of those special Tiger install CDs, but I doubt it.

But the whole reason that DOES come up for me is asking the first obvious question of what version of Mac OS you are trying to install. Tiger won't install on non-Firewire iMacs, and I don't think the 333MHz iMac has Firewire (as indicated by Everymac, it doesn't, and your iMac maxes out, officially, at Mac OS X 10.3.9).

The Mac OS 9 behavior is mighty odd, though. Even without a hard drive in there it should boot to the Mac OS 9 CD. Have you tried the ol' classic key sequence to reset the hardware settings on the device? option-apple-p-r at startup to clear out the PRAM might help, but it is unlikely.

If you're the industrious type you can always crack the machine open, disconnect the hard drive, and see if you can boot from CD. That will identify if it's actually the drive that's causing the problem or if it's something else.

(Mac OS X can be very particular and weird about hard drives. Yesterday I struggled with simply formatting a Seagate 80GB IDE drive in a USB 2.0 enclosure all day. Turns out I had to boot from my Tiger CD and format from the Disk Utility. Windows would format it, and 9.2 would initialize it, but Mac OS X's Disk Utility, even the command line version, completely crapped out on the drive if you had booted from a hard drive [any hard drive], but boot from the Mac OS X install CD, and ZIP, erase and formatted without a blink. Go figure.)

By: smallerdemon

smallerdemon — Tue, 20 Mar 2007 14:27:35 -0800

(*heh* Sorry to have answered after you'd already sorted it out, but I felt I had to mention the possibility of having a Mac OS X installer CD that wouldn't work with the model of iMac you have. Unlikely, yes, but not impossible.)

I am personally marking Malor's answer as a favorite myself to I can have that available for future reference. VERY useful information to have.