Funny thing - I CCCed my working drive to my test drive and rebooted to the test drive. The combo update hadn't been posted yet, so I used the updater to update to 10.6.5. Rebooted after update as usual and no sound. Ran MB and replaced the 10.6.2 AppleHDA.kext in S/L/E and got sound back. Spent about 2 hours testing everything I could think of and everything worked. Checked on the forums I follow for awhile and saw the post here that the combo update was available, so went and downloaded it. Was late (for me - I have to get up at 4:30 AM) so, when combo update finished downloading, I shut down and went to bed. Got home yesterday and booted normally, CCCed the working drive to the test drive again and rebooted to the test drive. Ran the combo update on the test drive and rebooted. It booted back to the desktop - no problem; check sound, no sound, restore 10.6.2 AppleHDA.kext again and have sound; run a few checks, looking good. OK, time to test restart, shutdown and sleep. Apple - restart command and the system shuts down like normal (or starts to anyway) hangs up after monitor loses signal and sits there. Waited 15 minutes and used the manual restart button. Booted normally, but no keyboard, so I couldn't select the test drive to boot off of. No problem. When I get to working drive desktop, edit com.apple.boot.plist time delay to 0 so it will stop at the darwin post screen - and reboot. At darwin screen, no keyboard - unplug and replug - no joy. Unplug and plug into front USB port - works. Select test drive and boot it up. This time test shutdown - no joy - it hangs at about the same place as the restart. Never shuts off - all lights are on, motherboard still powered up have to hold down power button till it shuts off. Thought it might just need to be cycled, so turned off all power at the power supply - wait 2 minutes, turn it back on boot up. At darwin srceen, no keyboard again, unplug-replug, no joy. Plug it into the back port again where it was before - hey! it works. Boot test drive again and try restart and shutdown tests again with same results. Secure erased test drive and reformatted it. Glad I didn't update my working drive!
OK, does anyone know - what is the difference between the software updater 10.6.5 update and the combo update? Why did one work OK, but the other is a disaster?