Hard Resetting the EFI on an Emac G4

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Joined: Oct 7 2008
Posts: 12

Hello everyone,

I found this mint condition Emac by the trash Wednesday. It's a G4 1.25 GHz, 512MB RAM, 80GB HDD and 32MB Video Card. I took it home to find out nothing was seriously wrong with it (nothing a few resets couldn't take care of). It has 10.4.11 installed on it and I wanted to wipe the system clean and install 10.5.6 Leopard. I soon find out that my Leopard DVD has a major crack in it. So I call up another friend and have him bring me over his Leopard DVD so I can have a clean operating system.

I put it in and all the sudden the screen starts flashing and not loading anything. I wait a minute to see if anything happens but it just kept flashing solid blue colors. I shutdown the Emac and when I turned it back on it just sits at the loading screen with the apple logo. I let it sit for around 20 minutes and it continues to so called "load". I later find out from him that the DVD he gave me wasn't a retail version of Leopard. It was a hacked version for use on intel computers! Somehow this really screwed up the computer, because now it just sits at the loading screen all day. I've tried a PMU reset, zapping the PRAM 3 times, doing the open firmware reset (reset-nvram, set-defaults, reset-all) and leaving the computer off and unplugged for a day. I've also tried single user mode, but when I try to restore the Emac that way it keeps repeating a string with "unsupported" written at the end. It repeats this many of times before finally freezing. It won't allow me to boot from cd/dvd either, not from holding the C key down or trying to boot a disc using open firmware. Because of this I only have access to open firmware and single user mode.

My friend says I need to do a hard reset of the EFI, does anyone here know how to that? If you can't do a hard reset of the EFI, is it possible to hard reset the logicboard? I remember with my Pentium 4 I messed around with the bios to the point the computer wouldn't turn on. I read online to remove the jumpers on the motherboard and keep the computer unplugged for an hour so it can discharge. Thus doing a hard reset of the bios. This worked wonders for resetting the bios on the Pentium 4 to factory defaults. Is there anyway to do a logicboard reset like I was able to do on the Pentium 4?

Any help is greatly appreciated.

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Dr. Webster's picture
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Joined: Dec 19 2003
Posts: 1687
PowerPC-based Macs, the eMac

PowerPC-based Macs, the eMac included, don't use EFI -- that's an Intel-based Mac function only.

Do you have a known-good, non-hacked OS X installation DVD?

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Joined: Oct 7 2008
Posts: 12
Hard Resetting the EFI on an Emac G4

Sorry, my mistake. Thank you for the correction.

No, I had an original 10.5 Leopard disc, but like I said it's cracked. I have an OS 9.2 generic install disc (which won't work on Emacs) and a 10.2 Jaguar Upgrade disc. I've tried to boot from the 10.2 Upgrade disc using the C key and open firmware, but no luck. It seems like I really need to hard reset the entire logicboard like I did with my Pentium 4 when I messed around with the Bios too much. I don't have any other bootable retail discs, just those I've listed. I've got images of 10.4 Tiger install discs on my external hard drive, but I'm afraid it might not work and waste my media. I don't have many blank cds left.

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Joined: Jun 29 2009
Posts: 60
no wonder why it won't boot from the cd

i have the same emac, the lowest os for it is 10.3, it won't boot from anything older than that. the emac is a great machine,well worth the few dollars you would have to spend to get new cds. you probably do not need to reset the motherboard, just get the cds. also, as long as your other mac are powerpc, you can use their disks, but it is not ideal

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Joined: Oct 7 2008
Posts: 12
Hard Resetting the EFI on an Emac G4

Geeko,

I had no idea that the Emac can't install anything before 10.3 Panther. I have a PowerMac G4 MDD Dual Processor with far more power than that Emac I found. As far as I know the MDD can boot down to OS 9. The fact the machine just sits loading all day made me think that the hacked Leopard DVD overwrote the firmware or something. Which might explain why the machine wouldn't boot from Jaguar. Thank you for this information, it's very helpful.

About 4 months ago I had original retail 10.3 Panther discs, but I sold them to someone on Craig's List. At the time one of the processor's on my PowerMac G4 Quicksilver was fried so I had to use my Windows machine for work. I can't tell you how much of a pain it was to use over the stability and simplicity of my Mac. I figured if I got another Mac it would have a more recent OS X on it and probably come with restore software. So that's why I sold the 10.3 Panther discs. I really wish I hadn't now.

Like I said in my previous post, I do have images of a retail version of 10.4 Tiger. I really like the Emac so I'm going to burn those images and try them out. If I ever need more blank cds I suppose I could just rewrite a couple of CD-RWs and use them. I rarely buy external media, especially blank cd/dvds.

coius's picture
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Joined: Aug 25 2004
Posts: 1975
I don't post here much but...

I would suggest hitting eBay for 10.4 discs, or even 10.5. 10.4 shouldn't got too much, and of course, if you post on Craigslist, you might find someone who has a copy that they might be willing to let you borrow to check the machine out. At least you will know what's working or whatnot. I also would then, if everything works, go out and by the discs. You can try 10.5, and it will work. You just need to get the Retail Disc. If you have a problem getting the disc I might be able to cut you a deal on my 10.5. I don't post here much, but if you want, shoot me an email at and I might be able to get that 10.5 to you for a decent price. I just upgraded to 10.6, and have a spare copy of 10.5 that I don't need.

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Joined: Oct 7 2008
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Hard Resetting the EFI on an Emac G4

Dr. Webster & Geeko, - Thanks for the useful information you've provided me. I burnt those 10.4 Tiger images and they worked! I'm surprised that the hacked 10.5 Leopard DVD overwrote crucial operating system files. From the sight of things, it just seemed like the machine was losing it from incompatibility. It didn't seem at all like it was overwriting actual files. Because I didn't get a chance to install the hacked 10.5 Leopard before it went on the fritz.

Everything is back up and running now. Thanks again!

Coius, - Awesome Yui-Ikari server you have running. Just goes to show that there are still quite a few uses for really old legacy machines.