Short version: Be careful with that latest QuickTime update if you have run any "DFU fix" Automator scripts on your unibody (Late 2008) MacBook or MacBook Pro. Do not upgrade to QuickTime 7.6 until you've repaired the alterations that the script made to your system. UPDATE: I am learning from commenters that this is not just limited to unibody Late '08 MacBooks, but it applies to ALL MacBooks running 10.5.6.

In this post, we outlined how to re-enable unlocking and jailbreaking functionality if you've upgraded to Mac OS X 10.5.6. To do it, you have to run an Automator script that "fixes" the system so that you can enter something called DFU mode. It's some hardcore juju, but the script seemed easy enough to run and reboot.

The now-mysteriously-missing original Hackintosh article mentioned that there were some issues with the unibody MacBook and MacBook Pros, but it never said that you should undo it after you finish jailbreaking.

I didn't even get the jailbreak itself to work on that machine in the end, even though Jason did on his unibody MacBook Pro, but the Automator DFU fix didn't cause any perceptible changes to my system's behavior, so I promptly forgot about it.

Fast forward two weeks. I get a notice of the latest QuickTime upgrade, so I OK it. When my system restarts, I have no access to keyboard or trackpad. Not only do I not have access, I can't even plug in a mouse or keyboard. I could use those controls when booting off of a system install disc, but I couldn't get the installer to repair my OS, since it was "newer." The computer was borked.

My solution was easy but nuclear: I turned an external 320GB drive into a boot disk, ran the migration tool to move every bit of data from my unibody MBP, then simply swapped drives. (Gotta hand it to Apple for that new swappable-drive design.) My machine is as good as new, and now totally up to date.

What you should do, if you already ran the DFU script and haven't installed that QuickTime update yet, is try the method I have since discovered outlined in this Apple Support thread. Apparently, I'm not the only one with this problem.

Here are a few solutions besides the one in the support thread:

• If you still have access to your keyboard and mouse, you can copy the backup files (it should be under Backup_IOUSBFamily_kext_10_5_6 on your desktop) to where the Automator script was, Install_IOUSBFamily_kext_10_5_5 on your desktop. Then, just run the Automator script again, and it will copy those "original" files to the right location, then change the permissions correctly and reboot your machine.

• If you already ran the QuickTime update and you're unable to access any input (USB or otherwise), you can SSH into your machine and run these commands one by one. If you had trouble with the Automator script, you can open up the terminal and do this too, manually. Note, some of these lines are too long, so they wrap to 2 lines. Make sure you copy it in its entirety. Commands are separated by empty lines in between.

sudo rm -R /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/AppleUSBHub.kext
You'll have to enter your administrator password here

sudo rm -R /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/IOUSBCompositeDriver.kext

sudo cp -R $HOME/Desktop/Backup_IOUSBFamily_kext_10_5_6/AppleUSBHub.kext /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/

sudo cp -R $HOME/Desktop/Backup_IOUSBFamily_kext_10_5_6/IOUSBCompositeDriver.kext /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/

sudo chown -R root:wheel /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/AppleUSBHub.kext

sudo chmod -R 755 /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/AppleUSBHub.kext

sudo chown -R root:wheel /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/IOUSBCompositeDriver.kext

sudo chmod -R 755 /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns/IOUSBCompositeDriver.kext

sudo rm -r /System/Library/Extensions.mkext

sudo touch /System/Library/Extensions

sudo reboot

Your machine will reboot after prompting to update boot caches, and the files should be back to the standard 10.5.6 ones. Good luck!

Update: If you're having trouble with update, try the combo one, per Lifehacker's suggestion.

Looks like a pretty commonplace list. A couple of standouts are better compatibility with AT&T 3G cards (maybe they don't summon a kernel panic if unplugged accidentally without disconnecting now?), MobileMe syncing within one minute on your Mac for any change made elsewhere, and general graphics improvements for gaming and elsewhere. And, finally, Chess.app has received the performance and reliability overhaul it has needed for so long.

Let us know if you spot anything else. [Apple - Thanks, Joseph!]

Address Book

* Improves reliability of Address Book syncing with iPhone and other devices and applications.

AirPort

* Improves the reliability of AirPort connections, including improvements when roaming in large wireless networks with an Intel-based Mac.

Client management

* Improves reliability of synchronizing files on a portable home directory.
* Fixes an issue in Mac OS X 10.5.4 and 10.5.5 in which managed users may not see printers that use the Generic PPD.
* Client computers that use UUID-based ByHost preferences now respect managed Screen Saver settings.

iChat

* Addresses an issue that could cause an encryption alert to appear in the chat window.
* Setting your iChat status to "invisible" via AppleScript no longer logs you out of iChat.
* Resolves an issue in which pasting text from a Microsoft Office document could insert an image rather than text.

Graphics

* Includes general improvements to gaming performance.
* Includes graphics improvements for iChat, Cover Flow, Aperture, and iTunes.
* Includes fixes for possible graphics distortion issues with certain ATI graphics cards.

Mail

* Includes overall performance and reliability fixes.
* Improves Connection Doctor accuracy.
* Fixes an issue that could cause messages identified as junk to remain in the inbox.
* Fixes an issue that could cause Mail to append a character to the file extension of an attachment.
* Addresses an issue that could prevent Mail from quitting.
* Improves reliability when printing PDF attachments.

MobileMe

* Contacts, calendars, and bookmarks on a Mac automatically sync within a minute of the change being made on the computer, another device, or the web at me.com.

Networking

* Improves Apple File Service performance, especially when using a home directory hosted on an AFP server. Important: If you are using Mac OS X 10.5.6 (client) to connect to a Mac OS X Server 10.4-based server, it is strongly recommended that you update the server to Mac OS X Server version 10.4.11.
* Improves the performance and reliability of TCP connections.
* Improves reliability and performance for AT&T 3G cards.
* Updates the ssh Terminal command for compatibility with more ssh servers.

Printing

* Improves printing for the Adobe CS3 application suite.
* Improves printing for USB-based Brother and Canon printers.

Parental Controls

* Addresses an issue in which a parentally-controlled account could be unable to access the iTunes Store.
* Includes general fixes for time limits.
* Resolves an issue that prevented adding allowed websites from Safari via drag and drop.

Time Machine

* Fixes issues that could cause Time Machine to state the backup volume could not be found.
* Improves Time Machine reliability with Time Capsule.

Safari
* Improves compatibility with web proxy servers.

General
* Includes Mac OS X security improvements. See this website for more information.
* Addresses inaccuracies with Calculator when the Mac OS X language is set to German or Swiss German.
* Improves the performance and reliability of Chess.
* Improves DVD Player performance and reliability.
* Performance improvements for iCal are included.
* Fixes an issue when running the New iCal Events Automator action as an applet.
* Adds a Trackpad System Preference pane for portable Macs.
* Improves compatibility with smart cards such as the U.S. Department of Defense Common Access Card.
* Updates time zone data and Daylight Saving Time rules for several countries.