EFI Modifications Leaves iMac Unbootable?

jerbare writes "In attempting to run Linux and Windows on the new iMac Core Duo, people experimenting with configuring the EFI Console/Boot loader have found they can no longer boot the machine at all. Dave Schroeder of appleintelfaq.com comments, 'We have already irreversibly lost a couple of iMacs trying to load various EFI modules'. Instructions for breaking the iMac's are presently located at the bottom of the comments."

Comments

Ugh...been there

[TripMaster Monkey]

Reminds me of a situation I faced back in the day when I was a tech at a small mom-and-pop computer repair establishment. We received a shipment of motherboards, and found out that the BIOS on every single one of them was corrupt. Since the boards wouldn't even post, the traditional remedy of flashing the BIOS via a bootable floppy was not available. Normally, we would have just boxed up the boards again and returned them for replacements, but we desperately needed those boards to fill orders.

Well, desperate times call for desperate measures...

I got to thinking, "you know...once you've started booting to an OS, that BIOS chip isn't even being used anymore....hmmm". With this in mind, I pulled a working BIOS from another board, swapped it out with the bad BIOS, and powered the system on, booting from the BIOS flash floppy. Once the board had booted to the flash program, I carefully pulled the good chip back out, and put in the bad chip. I then ran the flash program to overwrite the bad BIOS.

Long story short, it worked like a charm. I managed to revive every board in the bad shipment without incident using this unorthodox technique.

Anyway, it should be possible to rig up a similar arrangement here, although as I am unfamilliar with EFI, I'll leave the details up to someone else.

Re:Ugh...been there

[GmAz]

I did the same thing on my ASUS A7N8X-Deluxe motherboard. They shipped a bunch with their 3.3v batters running about 2.9v. Apparently this would corrupt your bios chip. Well, it did do that to mine and instead of ripping my machine apart and RMAing it, I took the bios chip from my brother-in-laws machine (I built his too and we pretty much had identical machiens) and did the swap trick. Here's a little trick for any of you wanting to try this. Before you boot up your good machine, take the bios chip out and put a piece of dental floss under it and put the chip back in. That way, when the machine is booted and you need to take it out to do the swap, just tug gently on the floss. I didn't wanna stick a metal screwdriver in there to pop it out when it was running. It worked great for me and spent $2 for two 3.3v batteries for the computers.

Dual Booting is not the answer

[ZachPruckowski]

I have a feeling that a virtualization/emulation with hardware graphics support will be available within 6 months that'll make dual booting pointless. I have a feeling that dual-booting OS X with XP or Vista will not work because it's got EFI/BIOS issues and the hard drive formatting issue. And any number of issues that haven't come up yet.

Re:Dual Booting is not the answer

[Incongruity]

Moreover, running a full windows install within OS X, through some sort of emulation/virtualization is going to be fairly easy as compared to, say PPC versions of virtual pc and it will potentially allow you to sandbox windows and thereby keep it much more secure than the standard installation on commodity hardware. Furthermore, there are few reasons to dual-boot if you can simul-boot? Done right, that method could really make the Intel/OS X macs a major player (think swiss-army knife) -- I know there's been talk of a similar sort of thing w/ linux and windows via WINE but it really looks like the OS X side might come to fruition first, though this really is all conjecture on my part, so whatever.

Re:Dual Booting is not the answer

[killtherat]

And why do you think that OSX will be able to run windows binaries better than WINE and/or Cedega considering that the people at WINE etc. have been trying to reverse engineer the windows libraries for many years now.

One word: Money.

Apple has lots of it. They can through gobs of money at the problem, and that will always move things faster then a grass roots problem. Just imagine 150 engineers working full time on Wine. They've previously gotten MacOS9 programs to run in MacOSX, so they probably already have a pool of engineers with the needed talents.

Given that MacOSX is based off of BSD Unix, and they've already plugged a great deal of work into the KHTML rendering engine, it's not completely insane to suggest that Apple could pick up Wine, through a large number of engineers at it, and get it to the point were it can run Office and DirectX 9 games.

Sometimes fix

[Anonymous Coward]

If you can get it to boot at all, try reinstalling from the 10.4.4 media. That's supposed to fix some changes in the EFI.

Denial Of Service - Putting people at threat

[NZheretic]

Hackers discover vulnerabilities and someone creates malware ( Worm, Trojan, Attack kit or Virus ) that screws with the BIOS settings effectively turning your DRM restricted system into a useless brick.

Just substitute Apple for Microsoft, Mac for Xbox and Internet for Xbox Live in the following...
Denial Of Service - Putting people at threat:

Want to guess how long it will take?

It is inevitable that someone mucking around trying to get their XBox360 to do something will trip the hardwired Trusted Platform Modules lock down. Effectively turning the trusted black box into a useless dead heap.

It is inevitable that this and other methods discovered will be publicly known, since the discoverer will want to warn others.

It is also inevitable this and other methods will become the basis for a widespread denial of service attack. Firstly through a fake Email campaign ( "Microsoft alert - follow these instructions to secure your XBox" or "Get Free games/porn - do this to your XBox" ) and later through viruses and networked worms embedded in Microsoft's mediaplayer formats.

Soon a worm that locks users out of their Xbox will be spread via Microsoft's Xbox live service.

Then it will be inevitable that criminals adapt the malware to display a message instructing the hapless victim how to make a payment to fix the problem. The messages would soon contain threats that their Xbox now contains contraband installed by the malware that would get the user in legal peril if they choose to take the Xbox back for repair or to the authorities. The potential rewards to the offshore cyber-criminals would far outweigh the risks.

http://itheresies.blogspot.com/2005_08_01_itheresi es_archive.html
Hollywood and the recording industry hold an effective monopoly on a large section of popular content. Both Microsoft and Apple are now offering the ability to content providers to demand that users must use unmodified systems to view said content. It locks you out of parts of your system that will inevitably be abused by third parties wanting to abuse you.

Posted by: David Mohring Posted on: 11/29/05

Re:Denial Of Service - Putting people at threat

[TheRaven64]

When the first flash BIOSes came out in the PC world there were a few viruses that would re-flash the BIOS with junk, turning the machine into a doorstop. These days most virus writers want to add your machine to a botnet, rather than destroy it, so it's probably less likely. More likely is hiding a copy of the virus in the EFI code so that it is automatically reinstated if removed when the system invokes an EFI call (resume from sleep would be my choice).

Ugly reality from the article (no joke)...

[Orrin Bloquy]

"Apples implementation of EFI allows software to modify the computers ability to boot - or NOT. "

Enough of this firmware is flash-based that software can trash it to the point that it no longer boots from optical media. Key-mashers need to understand that EFI *precedes* the Apple Option-key tricks, so if EFI is hung you are crap out of luck. Unless there's some jumper inside the case which resets EFI to a factory state, that EFI will have to be pulled and reflashed.

We're going to pretend Apple doesn't really release mistakes like this and that there's a failsafe for restoring the EFI. Otherwise, you potentially have the mother of all DRM traps in front of you.

Re:Ugly reality from the article (no joke)...

[Budenny]

The inability to reflash the EFI has all the marks of being deliberate. The issue is not whether other OSs are supported. There is no reason why any company has to support them. The issue is not like trying to run BSD on your Thinkpad, where you just reboot when you don't have the drivers and restart, and reinstall XP. Not having the drivers does not reduce your machine to junk.

The issue is, or rather, one should be cautious, the issue may be, that this could be the first instance of a company having deliberately implemented something that reduces your computer to a doorstop if you just take reasonable steps to run something they don't like on it.

They are under no obligation to support Windows, Linux or Plan 9. What they are under an obligation to do is give you a way of reflashing your EFL.

If they do not. If it does turn out that the aim is and always was to sell hardware that you can only run what they choose on it, then it is indeed the first shot in a war. It will be the first of many such attempts by a lot of people. The OP in this thread, and some others, is right: it will be the first of many efforts to stop you altering your machine in any way from its purchased state, because someone feels it is less profitable for them if you do, and it will be the first of many measures taken to reduce your machine to junk as a sanction.

Its one of those test cases the community has to win. If it turns out to be what it looks like, there's no melodrama at all in looking at it like this.

Update: iMacs restored to working state

[daveschroeder]

By following these steps, the iMacs that had difficulty with certain EFI modules appear to have been restored to a functioning state:

1. Disconnect the internal hard disk

2. Disconnect the iMac from AC power

3. Plug in AC while holding the power button

4. Power up the iMac and zap NVRAM (cmd-opt-P-R)

The hard disk can be reformatted and the operating system restored.

Re:Hey, Is this possible ?

[blueio69]

I think the best way to go about this would be to do something that was done to enable Linux to boot on old world Macs. On a PowerMac 8600 (for example) the best way to boot into PPC Linux, was to use a special boot loader called BootX http://penguinppc.org/bootloaders/bootx/. Basically, it was an OS 9 program that immediately ran as OS 9 had a basic initialization startup. It gave you a choice to ether to continue to boot into OS 9 or boot into Linux. It is unique from other boot loaders in that it bypasses a computer's firmware and lets Mac OS handle it. I think this is the way to go....let OS X handle the boot process that deals with the firmware, then give users a choice to boot into Windows or finish with the OS X boot process.