Ended up using DSDT editor to save existing system. Imported the modified DSDT file and rebooted. System appeared to be OK at first, but after I used the power button and selected sleep mode, the system did not sleep on screen, but system became unresponsive. Ended up power-cycling. Upon reboot, the system would get passed the selection to enter additional boot parameters, and would then hang on the Chameleon icon on the top of the screen. I was not able to recover the installation and started over clean. Still unable to sleep correctly and looking for options. SYstem is Dell E6410, i7, 4 GB. Installation based onhttp://www.insanelymac.com/forum/index.php?showtopic=219229&mode=threaded no errors but cannot update past 10.6.3