After installing the OS 10.6.7 combo update, I am unable to reboot without using iBoot. When I try, I get the bootloader screen, but the progress bar starts at about one third of the way in and then moves backwards to 0%. Then it just hangs on the grey Apple screen with no spinning wheel. Trying to boot from safe mode gives me a black screen with a row of blue characters that I don't think my keyboard has a key for. I installed using EasyBeast first, with these settings, but when that didn't work I tried the DSDT for the Gigabyte GA-H67A-UD3H-B3, still to no avail. Based on searching the forum, I suspect that this problem has something to do with the Radeon HD 5770, but I haven't come across a solution. Any suggestions would be much appreciated.