Intel imac problems

[namio]

I recently posted this on a couple of other forums but I haven't had any responses, so I thought I would give it a shot here. Hopefully someone will be able to suggest a solution

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I recently acquired a 24" Intel core 2 duo imac (2.16 processor, NVIDA 7600, 1gb ram - I believe it is the late 2006 model)

I purchased this imac knowing that the hard drive had died. I replaced the faulty hard drive with a 500gb western digital sata drive. The computer looks in good shape both internally and externally.

Everything appears to work - the optical drive, hard drive, graphics, start up chime etc

Here is the problem

When I try to install OSX from the supplied discs that came with the computer I get the following symptoms

1) The computer boots to a white screen with grey apple logo
2) The loading of the installation discs commences (little spinning logo under the grey apple)
3) After about 2 minutes, the spinning icon stops and the computer freezes - therefore no installation of OSX can take place.

So, I thought I would try to install OSX86 on it and I have managed to install both Kalyway 10.52 and idebian 10.55 with partial success

This is what happens

1) With both Kalyway and idebian, I am able to load the installer and get to the point of formatting the drive (in GUID - haven't tried MBR) At this point, I seem to have full graphics resolution. The installation goes as smoothly as it would on a PC.
2) Installation completes and I am able to boot up into OSX, but in very low graphics resolution (1024x768 only, no quartz etc). There is also no sound, but wireless internet works.

In order to boot into OSX, I have to use the efi 132 boot disc which allows me to choose the partition to boot from. If I try to boot the computer without efi 132, I get similar symptoms to those I described above - white screen, grey apple logo, OS starts to load as indicated by the spinning icon under the apple, then the computer freezes...

I have also restored the retail disc to a partition on the drive, booted up with efi 132 and have then been able to install the retail version of OSX, but again only in low graphics mode with no sound.

I have also been able to install winxp natively (ie no boot camp) and ubuntu linux...but again only in a low graphics mode, (interestingly there is sound with both ubuntu and winxp)

My thought is that somehow the efi boot rom on the imac is corrupt. I have managed to establish that there is information there (serial number, boot rom revision, SMC number etc) by entering the efi shell with rEFIt but I have no clue what I am doing in that rEFIt environment and whether or not I can edit/fix what might be a corrupt efi using rEFIt.

Other things - all the key commands (that I know) seem to work - the computer chimes, you press cmd -option, you can choose the drive to boot from, cmd-c, it will boot from the cd, cmd-option-p-r, resets the NVRAM, cmd-d starts the apple diagnostic disc if inserted (which detects no problems with the computer). I have swapped memory modules - replacing the 1gb with 4gb ram, I have reset the SMC by holding the power switch in while I reconnect the power cable, I have booted the computer with no hard drive, no mouse, no keyboard connected...all to no avail. I have also try apple's boot rom restore discs which are downloadable from their site (I tried version 1.4 and 1.6 of these discs but nothing happened when I tried to use them per the instructions on apple's site)

Currently where I am at is
1) I can boot into OSX with low res graphics and no sound using efi 132
2) I cannot install retail OSX from the DVD but I can if I restore the files to a separate partition and then boot from efi 132
3) If I try to upgrade either OSX86 or the retail OSX via software update, I end up with a black screen

Questions:

1) Why am I able to install winxp and ubuntu natively but not OSX, and why only in this low resolution graphics mode?
2) When I install OSX86, I get full resolution graphics during the install procedure but only low res/no sound after the OS is installed - does anyone have an insight as to why this might be?
3) Is there a way to check if the efi boot rom is corrupt on the imac and if so is it possible to fix it? (If anyone knows the answer to this and can help, I would appreciate it if could be explained as simply as possible for me)
4) Is this an efi boot problem or could it be something else?

I am baffled by all of this. The computer seems to be fine, all the components seem to work.

I 'think' this is something to do with efi and the way the computer boots initially (but I have no expertise in troubleshooting this)

Does anyone have any suggestions? Am I completely on the wrong track here?

Can anyone please help?

[aquamac]

Maybe your OSX disk that came with the computer is damaged in some way. What version is it? I would like to see this tried with a known working osx install disk of Leo. To be honest, you are going to have problems with OSX86 as it is not meant to be installed on a real mac. Your Hard Disk should be formatted as GUID, forget MBR on a real mac.

I was going to suggest memory and resetting of SMC, but it seems like you covered that.

Are you sure that the disk you have is the one that came with the mac or is it a retail disk?

[namio]

Thank you for your answer...

I have all the original discs that came with the imac. I have tried discs that came with another imac also (same processor - but a 20" as opposed to a 24" screen) The same problems occur when trying to install the 'official' osx - you get the white screen/grey apple logo and the little spinning wheel underneath it...but that just stops spinning and will go no further with the install) The only way I have been able to install osx is by using a boot 132 disc...then I can install either osx86 or the original discs (which is 10.47 btw)
I have tried to install retail version of leopard also but to no avail (unless I use the efi 132 disc)
The interesting thing is that when the installer is running, I seem to get full resolution on the screen....however after the installer has run and the machine boots in to osx, there is no sound and only very basic graphics)
I am sure the answer to fixing this lies in flashing or reprogramming the efi boot rom somehow, but I have no idea how to do that

[aquamac]

Maybe there is a firmware upgrade for your imac. Might be worth a check on the Apple website.

[namio]

Feb 2, 2009 5:27:10 GMT aquamac said:

Maybe there is a firmware upgrade for your imac. Might be worth a check on the Apple website.

Hi...thank you again for the reply. I believe the firmware in the imac is the latest - 1.6. I have tried various things from the apple site including an attempt to downgrade the firmware to 1.4 or 1.5 with no luck.

Is it possible that these symptoms could be caused by the previous owner attempting to install boot camp?

b

[aquamac]

Not sure, can you reinstall the latest firmware. You could try but it may not let you. It does sound like a firmware problem.