iBook won't boot: illegal instruction

When you're booting with the DVD you must press and hold the c-key during boot until you get the language screen. Is this what you're doing?

It could be a logic board or hard drive issue if it is a power issue and flashing is occurred. I am not exactly sure what the problem is though. You might want to check out:

http://www.myservice.com/ibook.html
http://www.myservice.com/harddrives.html
http://www.myservice.com/logicboards.html

They have a brief information about the problems. I am not suggesting that you buy anything from the site because I did not try it myself but the information could be useful.

Ok, Before going any further I suggest reseting both your PRAM and your PMU.

Rest PMU:

http://support.apple.com/kb/HT1431

Reset PRAM:

http://support.apple.com/kb/HT1379

Now, I'm not sure if the c-key is recognized as a proper boot command after mac-boot from firmware.

So the proper procedure for booting your Mac from DVD/CD goes as such.

1. Power on mac so that you can put the DVD into the drive then poweroff.

2. Power on Mac and immediately press and hold the c-key until you get the OSX installers Language screen.

3. Select your language then continue.

Now to run DU Disk Utilities from DVD.

4. The next screen will be the OSX installers Welcome screen, from the top menu bar select Utilities then Disk Utilities.

5. In DU, from the left pane select your drive. In the right pane select First Aid tab.

6. From the First Aid pane select to run "Repair Disk". If "Repair Disk" comes back with errors, run it again until no errors found.

7. Once "Repair Disk" is complete with no errors then select to run "Repair Permissions".

8. While in DU First Aid, Note at the bottom the drives S.M.A.R.T. status it should read "Verified".

If this does not fix the problem then you need to get an external drive with OSX loaded on it or another Mac (a friend maybe)so that you can try booting your Mac from one of them to verify that you don't have logic board problems.

I have the same problem with almost the same address quoted - mine says Illegal instruction at %srr0: ff85e778 %srr1: 00081010 (unless you mistyped %ssr instead of %srr, in which case we have exactly the same problem).

Most startup keys cause it to boot into Open Firmware (PRAM reset, holding option, C key for optical drive boot) and the only startup key that seems to work is T for target mode, when I finally got to eject the DVD that was stuck in there.

I have got it to start from an external drive (by getting it to startup from a Leopard install DVD and then using Startup Disk to point the machine at the external HD and restarting) and then run the entire suite of TechTool Pro tests over it which reported everything as fine apart from minor problems with Finder Info. Then I ran DiskWarior4 over it and replaced the directory and had all files and folders checked for corruption. Restarted to the internal HD and got bounced straight back into Open Firmware.

Still working on it, but happy for any input from someone who knows what the problem is.

further to the previous post:
I have also tried removing the RAM (even though it tested fine) amd reinstalling Leopard using Archive and install, neither worked. By default, the iBook is still booting into the Open Firmware (white) command screen.

Target mode doesn't always work, the open firmware (blue) bootscreen never works, PRAM reset has worked a couple of times (but still boots into OF screen) and starting holding the C key tends to boot from the DVD ok.

I know the installation of the OS on the internal drive is sound as I have used it to boot and run a PBG4 (by starting the iBook in target mode), but will not boot at all on the iBook. As mentioned above, the OSX install DVD boots the mac, and so does an external firewire drive (when set using Startup Disk whilst running off the install DVD)

The only other thing I can think of that might shed some light on it would be to replace the HD with a different one and seeing if it boots off that, but frankly I'm loathe to start disassembling an iBookG4 just to test something that is probably not going to work.

Can anyone suggest anything? I'm truly beginning to think this is a unfixable hardware problem.

Ok, so I decided to go in and check the airport card - and solved it!

I took the airport card out completely and powered up the iBook and it booted without any hint of the Open Firmware screen. Then I shut down, reconnected the airport card and put a small paper wedge in between the card and the bar that holds it down just to exert a tiny bit more pressure on the connection, powered up and it was still booting happily.

Hooray.

I too have the same problem with an iBook G4, booting directly into open firmware with the illegal instruction as the top line.
I searched Google and found others who said it's the Airport card.

Before the search it seemed to me that it was the Firewire port because the ibook would just lockup as random points when booted from the external hd.
I removed the single RAM chip (I think RAM is soldered to the mainboard too) and reseated it. Still the problem.
It seems that it could be a heat issue as the panics and lockups seem to happen more often when the iBook is warm/hot.
Zapped PRAM, reset open firmware, erased the internal hd-installed 10.4.6.
Still have the open firmware problem.

It certainly is a hardware problems, I guess I will have to take the iBook apart.

I wonder if the airport card has to be replaced or is the connection to the main board the problem

I'm wondering if the problem is that you are trying to install Leopard on a non-Intel iBook. My iBook G4 took Tiger with no problem. According to Apple, you need an Intel Processor Mac to run Leopard. Try reinstalling Tiger (if you have it) and see how it works. Make sure you are installing the correct Tiger on your iBook. Originally Apple released Tiger for PPC Macs, but at 10.4.4 they added an Intel version of Tiger. Make sure you're trying to install the one for PPC processors.

Message was edited by: Erica Munton

Leopard (10.5) will install fine on most PPC laptop or desktop (processor has to be fast enough). Snow Leopard (10.6) will ONLY install on an Intel laptop or desktop.
I have the original Apple installer for the iBook and it is crashing into Open Firmware after a reformat and clean install.
There is some kind of hardware problem but even the extended hardware test did not find any problems.