Unable to Reboot After Latest Apple Updates (SA-2011-06-23-1 and Security Update 2011-004)

Question

Hi All,
After applying today's updates (06/23/2011) in APPLE-SA-2011-06-23-1 Mac OS X v10.6.8 and Security Update 2011-004, my MacBook will no longer boot. Prior to updating, the MacBook workked perfectly (except for the occasional error entry in the system and kernel log). The MackBook model number is A1278, with a RAM upgrade (4 GB).
When booting in NORMAL mode, the grey screen with Apple logo (and spinning wheel) is shown for about 50 seconds. The device never shows the blue background or login window. It simply shuts down like the power was pulled.
When booting in SAFE mode, the grey screen with Apple logo (and spinning wheel) is shown for about 1 minute 30 seconds. The blue background is shown and quickly transitions to the login windows. About 45 seconds after the login window is shown, the machine shuts down like the power was pulled.
On the few occassions I logged in to take advantage of the 45 second safe mode window (before shutdown), I was *not* able to copy off my log files (in /log/var) to a thumb drive because the computer would not mount the USB device.
When I peeked at the system's log file, I caught the tail end of "signature validation failed" for a bunch of hardware - from video to audio. I can only peek because the computer will shutdown before I have an opportunity to study anything in detail. The failed verifications may or may not be related to the shutdown - signature verfication might be disabled in safe mode; I simply don't know.
It seems the world's most advanced operating system [tm] is performing the world's most epic failure. Any ideas to get this brick working again would be greatly appreciated.
Jeffrey Walton
Baltimore, MD, US

Answer 1

Here's what I've found:
(1) I cannot run Disk Utility because I don't have my install disk handy
(2) I cannot run Repair Permissions because Apple does not make a separate ISO available to fix their mistakes
(3) There does not appear to be a wat to back out updates (ie, no Add/Remove Programs)
I was able to boot into safe mode and perform:
    > sudo bash
    $ chmod -R root /
Amazingly, the command ran to completion. Unfortunately, it did not fix the problem. As soon as some spare cycles were available (interesting indeed!), the machine shutdown.
+1 to Apple engineers for creating a broken patch
+1 to Apple quality assurance for letting the junk out the door
+1 to Apple, for not offering an ISO to fix a broken installation
+1 to Steve, who has managed to keep his anti-trust lock on the hardware and broken software
Great job, Apple