Chosen Solution

Unit Description Serial Number: W87130ZKVGN Type: iMac “Core 2 Duo” 2.16 24-Inch (T7400) Intro.: September 6, 2006 Disc.: August 7, 2007 Order: MA456LL Model: A1200 (EMC 2111) Family: Late 2006 - 24" ID: iMac6,1 RAM: 2 GB VRAM: 128 MB Storage: 250 GB (7200 RPM) Optical: 8X DL “SuperDrive” Problem Description All attempts to boot the system from any media result in a kernel panic. What has been tried

  • Checked that it makes all the right “chime” noise on startup, before the apple and spinning gear.
  • Booted into single user mode and was able to access hard drive file system without errors. Was able to mount the HD as read/write and run standard repair/diagnostic cmds from the command line. Also ensured permissions were correctly set. Suspect the hard drive is actually OK, but still could be corruption of O/S boot files. Not sure if this would cause kernel panic when booted from CD with HD still attached.
  • Holding down option key on startup works OK. Shows the partitions on the hard disk and other O/S boots available on recovery partition, USB or DVD. It will try to boot off selected item, but fails with kernel panic.
  • Holding down shift key on startup shows the progress bar and completes that phase, but kernel panics prior to displaying menu.
  • Holding down D key on startup works as previously noted. Extended diagnostics show no errors.
  • Holding down command V (verbose mode) works to the extent of showing boot process, but eventually kernel panics.
  • Resetting SMC and PRAM doesn’t help.
  • Prior to this the unit didn’t give any indication that any hardware was failing or software was corrupt.
  • Disassembled and inspected unit for any obvious loose connections or damaged components. Found none.
  • Pulled the hard-drive cable and verified that I got a file folder with a flashing “?” on startup.
  • Tried booting from DVD with HD cable disconnected. Still causes kernel panic.
  • Swapped various amounts of RAM in and out, plus tried running on just one of the two slots without any success. Supplemental Info Originally suspected just a bad hard drive, because of only getting as far as white screen. Subsequent testing with the original install disk indicated that the actual issue was a kernel panic, since a text message to restart the unit was displayed.

Unanswered from your previous question: Tell me about this boot disk you are using, is it grey? What are the part numbers on the disk? What is the other Mac you are using? Do you know how use Target Mode? Kernel Panics can either software or hardware related but at least you are to a screen now. At this point I would boot it into Target mode using a firewire cable. Run Disk utilities on the hard drive. We can go further but I need to know the other Mac is first and what system it is running. https://en.wikipedia.org/wiki/Target_Dis…

What revision number is the ROM in the Geforce 7300 GT? On a “broken” iMac 24 that I got recently, I did a T-boot and used Disk Utility (on the good Snow Leopard iMac) to “restore” (copy) the good HDD to the sick iMac. Then, it would fully boot into Safe Mode! However, any regular boot (from the HDD, and DVD, or any USB flash stick) fails, freezing on a white, grey, or black screen (sometimes with the cursor arrow movable). Since the HDD seems good (and should not even be used if booting from DVD), and Safe mode shows the full desktop, I am guessing that there is a mismatch between the iMac’s boot rom and the strange revision I see on the 7300 GT’s ROM. I expext 3022, possibly 3021, but not the 3467 revision that I see. Please, how can I re-flash the 7300’s ROM back to revision 3022? I am hoping that would cure the problem.